IAWA Journal, Vol. 15 (1), 1994: 3-45 SURVEY OF ENGLISH MACROSCOPIC BARK TERMINOLOGY by Leo Junikka 1 Department of Botany, P.O. Box 7 (Unioninkatu 44), 00014 University of Helsinki, Finland Summary Tenns of outer and inner bark characteristics are critically surveyed. Different macroscopical tenns with their synonyms are listed for a comparison of bark features. Suggestions are given for a standardised usage of the tenns to stimulate a practice of pertinent field notes and facilitate understanding of descriptions. Preferred tenns are printed in bold face and preferred definitions in italics. Key words: Bark morphology, tenninology. Introduction Notes on the appearance of the bark or the fonn of a trunk are often wanting or inadequate in most tropical floras. Only a minority of plant collectors include various field characters on the labels of herbarium sheets. However, careful descriptions of mature barks and other vegetative parts, especially in rain forest trees, may provide a valuable tool for reliable and quick plant identification. Plant collectors often cannot reach the crown canopy of the rain forest emergents, or if they obtain a branch sample, there may be no flowers or fruits. Furthermore, the tedious process of naming plants belonging to certain families or other taxonomic units which are notoriously difficult to identify in the herbarium might be greatly speeded up if good bark characters were available. This, in turn, could prevent undue delay in publishing, for instance, the results of inventories of tropical forests. There have been several attempts to construct keys based on bark characters. Presumably, Lely (1925) from Northern Nigeria and Foxworthy (1927) from the Malay Peninsula were the first who carefully listed different 1) field characters of valuable timber trees with notes on barks. They were followed by Beard (1944; Tobago), De Rosayro (1960; Ceylon), and Den Outer (1972; Ivory Coast). Whitmore (1962a, b, c), in his notable studies on Dipterocarpaceae, described seven distinct bark types and demonstrated that the bark may provide valuable taxonomic information, and may shed light on a number of important taxonomic problems. Voorhoeve (1965) produced a comprehensive study of some Liberian high forest trees with a great deal of infonnation on bark characters. Roth (1981) summarised studies on tropical barks in Venezuelan Guyana with some characters and definitions worthwhile to comment. In recent years good examples of tree floras using different bark features are Tailfer's (1989) work on tropical Africa and Polak's (1992) work on Guyana. Thus good data are available, but only from a few areas and, virtually, only from a few plant groups such as the genus Eucalyptus (Francis 1951) or the family Dipterocarpaceae (Whitmore 1962c). In contrast to the strong standardisation in wood anatomical terms by the lAW A (1957, 1964, 1989), bark anatomical terms were reviewed to a certain extent by few authors only, e.g. Esau (1969) and Martin & Crist (1970). Later a thorough discussion of various tenns with references to relevant literature and proposal of a list of bark anatomical terms to be used was published by Trockenbrodt (1990). The present paper concentrates on bark morphology. As the anatomical composition of the bark highly contributes to the outer aspect and other characters of the bark, terms Temporary: Herbarium, Department of Plant Ecology and Evolutionary Biology, University of Utrecht, The Netherlands. Downloaded from Brill.com01/25/2021 05:12:32AM via free access 4 used in bark anatomy and those used in bark morphology overlap to a certain degree, particularly those concerning bark tissues. The first efforts to compile a descriptive morphological terminology of barks were made by Wood (1952), De Rosayro (1953), and Wyatt-Smith (1954). These papers were mainly concerned with bark features based on the authors' own experience from Southeast Asia. Also some terminological definitions of bark features are included in the glossaries of tree floras, such as Corner's book 'Wayside trees of Malaya' (1940; 3rd ed. 1988). Various terminological notes can be found in textbooks of tropical botany. A good example is Letouzey's (1986) book 'Manual of forest botany' in two volumes on tropical Africa (translation from the original French, 1972). Among plant anatomical textbooks, Eames & MacDaniels (1947), Esau (1960, 1965, 1969, 1979), and Fahn (1990) have referred to macroscopical characteristics of barks. Rollet (1980, 1982) published a review about the variability of characters used in macroscopic bark analysis. Based on his survey of field floras that contain notes on bark features, and his own experience from the tropics, he described the potentiality of using bark features, giving numerous examples. As Trockenbrodt (1990) has pointed out, the large number of terms with partially or wholly overlapping meaning "reveals the lack of a concise and widely applicable terminology of bark structure." Not only are different morphological terms applied to the same structure but also, in some cases, a term is obscurely defined, thus allowing different meanings. The main difficulty with regard to bark morphological descriptions is that features which are pure responses to the environment have to be distinguished from those which are inherent to a particular species. One has to know the variability of barks: between individuals of the same species variation is often considerable, and even in different parts of the same individual. Only efficient collecting of data from a large number of mature trees using accepted and standardised descriptive terms will enlarge the knowledge of bark variation. A simple and well-defined terminology is, therefore, a prerequisite. IAWA Journal, Vol. 15 (1),1994 This paper is intended as a proposal toward a consistent bark morphological terminology. I have quoted 'representative' definitions from the anatomical literature, from some field floras of different geographical areas, and from common botanical textbooks written for tropical areas. Some well-known terms have been omitted, although some synonyms are accepted. I have restricted the scope of this study to the English literature, but some common terms (e. g. rhytidome, phloeme) from French publications are included. This tentative list of terms certainly does not pretend to cover all the terms used in botany and forestry. Hopefully, though, it will bring more clarity in a rather confusing bark terminology, and thus contribute to a badly needed standardization. Structure, symbols, and abbreviations used in the list Structure This paper is divided into three main chapters: 1) a list of accepted terms, 2) a survey of the terminology with the accepted definitions, synonyms and comments on relevant literature, and 3) a list of rejected terms with many cross references. The accepted terms are printed in bold face, and the accepted definitions in italics. The survey of the terminology (and the preceding list of accepted terms) is subdivided into five parts, dealing with: I II III bark and its component tissues bark texture bark patterns a. bark patterns in tangential and cross sections b. fissuring c. exfoliation d. external markings N exudation V bark cutting Entries are printed in alphabetical order and the attributes within an entry are arranged according to its meaning. Numbers between parentheses, (1), (2), etc., indicate two or more meanings of a particular term. The definition of a term by its original author has been Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology maintained, as far as possible. Sometimes an author did not define a term explicitly, so that its meaning had to be deduced from the original context. Often the original definitions had to be abridged to save space. For practical reasons some definitions are placed under entries in the chapter on rejected terms, but they are commented upon in the list of accepted terms. Symbols * ~ is placed after a reference showing a direct quotation from the source. refers to the term under which an explanation is given, and which is usually preferred. an alternative term which is also accepted. the cited author has explicitly used the synonym in the sense given here. Cf. confer =compare with. Inc!. the term is included in the definition proposed for this entry. See an explanation is given under the indicated entry, which is not synonymous. Syn. rejected synonym(s). Abbreviations AHDE American Heritage Dictionary of English language (1980) Ba Bena (1960) BCFTl British Commonwealth forest terminology 1 (1953) BCFT2 British Commonwealth forest terminology 2 (1957) Be Beard (1944) BKI Brooker & Kleinig (1990a) BK2 Brooker & Kleinig (1990b) BM Bi.isgen & Mi.inch (1929) Bor (1953) Bo Br Brown (1971) Cg Chang (1954) Cha Chattaway (1953) Ck Craddock (1932) Comer (1988) Co Dirr (1977) Dr Edlin (1976) Ed 5 Ed Edlin (1976) Eames & MacDaniels (1947) Esau (1960) Esau (1965) Esau (1969) Esau (1979) Fahn (1990) Ford-Robertson (1971) Francis (1951) G6mez-Vazquez & Engleman (1984) Ghouse & Jamal (1978) Hightshoe (1989) Hall et al. (1970) Howard (1971) lAWA, Committee on Nomenclature (1964) Ir Irvine (1952) Ja Jackson (1928) Ji Jimenez-Saa (1973) Kr KrUssmann (1984) Ku Kunkel (1965) Letouzey (1986) Le MC Martin & Crist (1970) Me Metcalfe (1979) MET Macdonald Encyclopedia of Trees (1982) MW Meijer & Wood (1964) Nu Nultsch (1971) Oul Outer, den (1967) Outer, den (1972) 0u2 Po Polak (1992) PW Penford & Willis (1961) PZ Panshin & De Zeeuw (1980) RDMB Radford et al. (1974) REC Raven et al. (1976) Ro Rollet (1980, 1982) Rt Roth (1981) Ry Rosayro, de (1953) Srivastava (1964) Sa SAF Society of American Foresters, Committee on Forestry Terminology (1950) Storrs (1979) Ss Thrower (1988) Th Ti Timberlake (1980) Vo Voorhoeve (1965) Whitmore (1962a) Whl Wh2 Whitmore (1972) Wo Wood (1952) WS Wyatt-Smith (1954) Wy Wyk, van (1985) YYI Yunus et al. (1990) EM Esl Es2 Es3 Es4 Fh Fo Fs GE GJ Hi HJC Ho IAWA Downloaded from Brill.com01/25/2021 05:12:32AM via free access IAWA Journal, Vol. 15 (1),1994 6 ACCEPTED TERMS: DEFINmON AND COMMENTS I. Bark and its component tissues (Many terms commented upon here are indicated in the schematical drawing in Fig. 1) bark, inner bark (1) all tissue outside the vascular cambium regardless of its composition (Trockenbrodt 1990*). Syn.: rind (Ck, BM, Ja). (2) in dicotyledons the term bark in a popular sense is applied to all secondary tissues external to the xylem in stem and roots of woody plants (Metcalfe 1979*). (3) a dead outer protective tissue of woody plants, derived from the cortex; varies greatly in appearance and texture; often including all tissue from vascular cambium outward (Dirr 1977*). (4) -t I: rhytidome (1), (2). Comments: In plants with secondary growth bark consists of the secondary phloem, the primary tissues still existing outside the secondary phloem, the periderm, and the dead tissue outside the periderm. Metcalfe (1979) omits primary tissues from the definition of bark. Dirr's (1977) definition has to be rejected, as it is self contradictory. Although the etymological root of the term bark is the same as the German 'Borke', meaning rhytidome, there is no practical reason to change the well-established definition of the bark (1). II I I Ii II " II ~~'~'~~'~I~~~~I/ periderm [ rhytidome phellem phloem inner bark \=~~~~::t----=.ca mbium xylem Fig. 1. Suggested terms for the tissue zones resulting from rhytidome formation. (1) = I: phloem. (2) -t I: phloem, non-collapsed secondary. (3) the living part of the bark inside the innermost cork cambium (Raven et al. 1976*). Syn.: blaze (Be), live bark (Wo, Ba, Ji), living bark (Po). (4) adherent rhytidome under the easily detachable scales and the tissues below it (De Saint Aubin 1963). (5) -t I: periderm (1). Comments: Martin & Crist (1970) propose that anatomists refer to the inner bark as phloem. Trockenbrodt (1990), too, recommends a more accurate expression instead of inner bark. He suggests the expression 'living secondary phloem' or 'secondary phloem up to the lastformed periderm'. Although the term phloem is mostly favoured by anatomists, the term inner bark is accepted here as an alternative, because many non-anatomists use it frequently. In this sense, inner bark or phloem is complementary to outer bark or rhytidome. Other meanings of the term should be avoided. bark, outer (1) = I: rhytidome (1). (2) -t I: rhytidome (2). (3) -t I: rhytidome (3). (4) used by Roth (1981) in the microscopical description of the outer layer of the phloem where "the proper arrangement of cells and especially the pattern produced by the hard bast, is disturbed by active dilatation growth." Cf: I: phloem, collapsed secondary; bark, middle (1) (rejected term). See comments under I: rhytidome. bark fibre fibre in the bark (Trockenbrodt 1990*). Syn.: bast fibre (Esl). See comments under I: phloem fibre. Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - 7 Macroscopic bark tenninology bast (1) any fibres of the outer part of the plant, though mostly obtainedfrom the secondary phloem. Syn.: bass (EM!). (2) --+ I: fibre, phloem. (3) --+ I: phloem, secondary phloem. (4) --+ 1: phloem. See comments in Trockenbrodt (1990). cambium many species of Eugenia, it darkens purplish on exposure (Wyatt-Smith 1954). A purplish stain is, in fact, left on the knife when cutting the phloem. This is a useful distinctive feature (De Rosayro 1953). Rollet (1982) mentioned that in some cases rapid discoloration takes place in vascular cambium after slashing. I have not found any mention of the colour of phellogen. The meristem fonning dilatation tissue commonly is not included in the definition of cambium. a meristem with products of divisions arranged orderly in parallel files; consists of one layer of initials and their undifferentiated products, or derivatives (Esau 1960*). Syn.: lateral meristems (REC). cork Applied only to the two lateral mcristems: cortex vascular cambium: the meristematic cell layer responsible for the development of the wood and/or the phloem. Syn.: wood cambium (Ed), main cambium (Ed). pbellogen: the meristematic cell layer responsible for the development of the periderm (Trockenbrodt 1990*). Syn.: bark cambium (Ed), cork cambium (lAWA!, Esl!, Ja!, Br!, BCFT2!, Oul!, Fh!, Cha!, Whl!, SAP!, BM, REC!, Ry, PZ!, Cg!, Ck!, Nu!, EM!), cork meristem (Ja!). Cf: I: peridenn; I: phellodenn; I: phellem. There are also other meristems which fonn additional tissues: dilatation meristem: a radially oriented meristematic cell layer in the phloem ray of some plants; responsible for adistinctly funnel-shaped phloem ray dilatation (Trockenbrodt 1990*). Comments: Meijer (1974), Raven et al. (1976), and Fahn (1990), following Esau (1960), use the term 'cambium' in both senses. Some authors (Jackson 1928, BCFTI 1953, Wyatt-Smith 1954, IAWA 1964, Den Outer 1967,Panshin & De Zeeuw 1980) have restricted it to vascular cambium only. Vascular cambium is frequently inconspicuous. If visible, it is usually translucent or watery, but, for instance in (1) a trade product which is mainly extracted from the cork oak tree (Quercus suber). (2) --+ I: phellem. See comments in Trockenbrodt (1990). (1) the tissue of primary origin that belongs neither to the epidermis, the periderm, or the phloem; between epidermis (periderm) and the vascular system (Trockenbrodt 1990*). Syn.: primary cortex (Me, BM), periblem (Ja!). (2) --+ I: rhytidome (1). See comments in Trockenbrodt (1990). dilatation tissue all tissue affected by dilatation growth (Trockenbrodt 1990*) (Fig. 2). Syn.: intercalary proliferation tissue (Whl), expansion tissue (Wy). Incl.: radial inclusions (Ji), wedges (Po). C!: lILa: dilatation (growth); lILa: streaks. Comments: Different parts of the tissue may undergo a dilatation process caused by the tangential strain which is a result of an increase in diameter of stem. Dilatation growth patterns, often with distinct colour, should be described by drawings and short notes when they fonn discernible patterns in the phloem. Voorhoeve (1965) points out that dilatation tissue often appears in different-coloured and -textured vertical bands and stripes. These markings are good characteristics, as Rollet (1982) has demonstrated in the family Annonaceae. Downloaded from Brill.com01/25/2021 05:12:32AM via free access IAWA Journal, Vol. 15 (1),1994 8 periderm (1) the secondarily developed protective bark tissue replacing the epidermis, or built during rhytidome formation; consists of phellem, phellogen, and phelloderm (Trockenbrodt 1990*). Syn.: secondary cork (Oul !), corky layer (Ja), inner bark (Kr), occasionally used in the meaning of phellem (lAW A 1964), laminae in dead bark ('laminated dead bark') (Ji). Cf: I: phellem; I: phellogen; I: phelloderm. (2) the outer bark or epiphloem, ... cork cambium and its products (Jackson 1928*). Comments: The first-formed periderm originates most commonly in the subepidermal layer. In older trees last periderm separates dead outer bark from living inner bark which consists of secondary phloem (Esau 1960). The arrangement of periderm layers may vary with the species and/ or different parts of the stem, when seen in cross section. Meijer & Wood (1964) mention that some species of Shorea may have differently coloured periderms in the same tree, but generally they show a uniformly coloured periderm which is characteristic for the species. See discussion concerning periderm in Trockenbrodt (1990). phellem a secondarily formed protective tissue in stems and roots consisting of dead cells with chiefly suberised walls; developed outward from the phellogen and forming a part ofperiderm. Syn.: cork (EsI!, Ro, Rt, Ja!, IAWA!, Oul!, Fh!, MC!, Whl!, Cha!, Me!, Ho!, SAF!, REC!, BM, Cg!, Ck!, EM!, Br!, BCFT2!), cork cortex (Ja), inner surface of the dead bark (Ji)? Cf: I: periderm; I: phelloderm; I: phellogen. Comments: Suberised walls of phellem have waxy or fatty material resistant to the passage of gases and water vapour, isolating the outer parts of the bark. When developed, phellem frequently forms a strong tissue and may result in a persistent bark, even though deep cracks may develop (cf. examples like Betula, Robinia, Sequoia; Esau 1960). According to Eames & MacDaniels (1947), generally several to many times more phellem cells are produced than phelloderm cells, although there is a great deal of variation in different plants. Trockenbrodt (1990) restricts the term 'cork' to the trade product obtained from cork oak. phelloderm a secondarily formed living tissue developed inwardfrom the phellogen,forming a part ofperiderm and resembling cortical parenchyma. Syn.: middle bark (Ry!, WS, Wh2), secondary cortex (Whl!, Ck), cork skin (RECl), outer edge (Wo!). Cf: I: periderm; I: phelloderm; I: phellogen. Comments: The phelloderm may be thick- or thinwalled, and probably gives some protection against pathogens, heat and desiccation (Martin & Crist 1970). The phelloderm is usually a thin layer and generally indistinguishable from the inner bark, except when it has a distinctive colour (De Rosayro 1953). Wood (1952), Wyatt-Smith (1954), and Rollet (1980) consider its colour generally a valuable feature for diagnostic purposes. According to Whitmore (1962a), it usually occurs as a distinct, up to I mm thick, red-brown layer of soft powdery tissue in Dipterocarpaceae. This coloured layer, usually found under thin, easily chipping rhytidome of some species, may be streaky and sometimes the colour of the just peeled piece may be different from the piece after longer exposure. This is a highly diagnostic feature in such genera as Kokoona and Lophopetalum (Whitmore 1972). However, usually one finds under a thin rhytidome a green layer, which is too common to be of diagnostic value (Rollet 1980). phellogen, see under I: cambium. phloem = I: inner bark a principal assimilate conducting tissue composed of different tissues and usually Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology located outward of the xylem and inward of the periderm. Syn.: inner bark (WS, lAW A, MC, Oul!, Ho, Cg, Ry!, REC, GJ, Br, Ro, SAF!, PZ, Wo, Ed!, GE!, Wh2), bast (Ro!, SAF!, MET, Ed!, Ja!, BM, Ry), inner rind (BM), live bark (Ro i), liber (Ja, MET), bass (Fo). Cf: I: bark, inner (3); bark, middle (1) (rejected term). Phloem can be divided into: primary phloem: phloem of primary origin (Trockenbrodt 1990*). Syn.: primary bast (Ja!), primary cortex (Rt). secondary phloem: all bark tissues derived from the vascular cambium during secondary growth (Trockenbrodt 1990*). Syn.: secondary bast (Ja), secondary liber (Ja), secondary cortex (Rt, Ja), bast (Oul!, Ou2). Secondary phloem can be subdivided into two layers that are sometimes visible to an unaided eye: non-collapsed secondary phloem: part of the secondary phloem with open and non-collapsed sieve-elements (Trockenbrodt 1990*). Syn.: functional phloem (Esl, Sa, REC), functioning phloem (Es3, Es4, Fh), conducting phloem (Es2, Es4, Wh 1, Rt), conducting zone (GJ), inner inner bark (WS), inner bark (Ro, Rt), inner layer (of the live bark) (Ji). collapsed secondary phloem: part of secondary phloem where sieve elements, companion or Strasburger cells, and sometimes axial phloem parenchyma cells are collapsed (Trockenbrodt 1990*). Syn.: non-functional phloem (EsI, Sa, REC), non-functioning phloem (Es3, Es4, Fh), non-conducting phloem (Es2, Es4, Whl, Rt), non-conducting zone (GJ), non-active phloem (Fh), outer inner bark (WS), outer bark (Ro), outer layer (of the live bark) (Ji). Other structures in the secondary phloem that can sometimes be distinguished with an unaided eye: 9 scIerenchymatic elements: fibres, sclereids, and their intermediates forming various structures in the secondary phloem. Patterns thus formed may be seen in cross and tangential section. Syn.: hard bast (BM, Ro, Rt), hard bark (IAWA), stereome (BM!), inclusions (fibrous -, grid-fibrous -, and sandy inclusions) (Ji). Note! Sieve elements, companion cells and phloem parenchyma are called soft bast, soft bark or leptome respectively by some authors. Cf: bast (2) (in rejected terms). phloem rays: rays traversing the phloem (Trockenbrodt 1990*) Inc!.: striated inner bark (WS). Comments: The general arrangement of the tissues of the phloem is governed by the interaction between the products of the vascular cambium and the dilatation tissue. According to Whitmore (1972), phloem usually plays a role of little value for tree identification. However, there are some aspects of morphology, colour, texture, exudate, and smell which are shown to be worthwhile. Wyatt-Smith (1954) suggests subdivision of living phloem into 'outer inner bark' and 'inner inner bark' in some cases, corresponding to Wood's (1952) terms 'outer layer' and 'inner layer', although he does not always consider it feasible. The distinction is made on grounds of disparity in texture and colour. Equally, Rollet (1980) and Roth (1981) distinguish outer bark, inner bark, and middle bark within the phloem, although Rollet prefers to avoid the term middle bark and, instead, speaks of outer bark with or without the dilatation zone. However, Wyatt-Smith (1954) and Whitmore (1972) adopted the term middle bark in a completely different sense, referring to an often coloured phelloderm in some species. Rather than adopting a highly confusing terminology as just discussed, a simple subdivision of phloem into non-collapsed and collapsed phloem may suffice. These terms correspond well enough to macroscopical aspects like colour, texture, and occurrence of dilatation tissue. The term middle bark Downloaded from Brill.com01/25/2021 05:12:32AM via free access 10 IAWA Journal, Vol. 15 (1),1994 should be avoided, as Trockenbrodt (1990) proposed. According to IAWA (1964) terminology, hard bark sometimes occurs in concentric layers that alternate within a growth ring with layers of soft bark, or are more irregularly distributed in a ground tissue of soft bark. Here such structures in the phloem are called 'phloem with laminated texture'. In macromorphological studies it is sometimes possible to distinguish between sclerenchymatic tissues and parenchymatic or dilatation tissues, mainly because of differences in colour. Therefore, the term sclerenchymatic elements is suggested for all sclerified structures observed in a cross section. Reliable identification of different layers can be obtained only in microscopy. The phloem rays are frequently much affected by the collapse of sieve elements and associated cells, and by stem growth. The wide phloem rays commonly become dilatated by cell division and tangential extension of cells. They remain radial, but they flare toward the periphery of the stem. The narrow rays commonly become curved (Esau 1979). Wyatt-Smith (1954) described striated inner bark in which radial stripes of a different colour, often white, are visible, for instance in Annonaceae. Furthermore, they are connected with the fissures in the rhytidome. Apparently these radial stripes are rays dilatated in a different way. phloem fibre bark fibre of the phloem (Trockenbrodt 1990*). Syn.: bast (Ja, EM, BCFT2, Fo), bass (EM, BCFT2 !), bast fibre (IAWA, PZ, Ja, Nu!, Oul, Es1), hard bast (Nu, Ja), liber fibre (Jat). Cf: II: texture fibrous. Comments: Fibres are taxonomically important. When they occur in the secondary phloem, they are conspicuous elements because of their thick walls and characteristic distribution patterns (Esau 1979). They occur in a variety of form and arrangement, often in definite tangential bands (Liriodendron, Populus) or solitary (Cephalanthus). In some woody plants with a hard, tough bark (Carya), the fibres make up the greater part of the secondary phloem and provide considerable mechanical support for the stem (Eames & MacDaniels 1947). See Trockenbrodt (1990) concerning the terms 'bast', 'bast fibre', and 'hard bast'. rhytidome (1) = I: outer bark the dead outer part of bark including the last-formed periderm, cut off by this peridermfrom still living secondary phloem. Syn.: outer bark (Esl!, Fh!, REC, Br, Cg, Ed, MC!, Whl), bark (MET, Ja), cortex (MET), rind (Ja), outer rind (BM), primary rind (BM), true bark (Ed!, Ir), scale bark (EM!), shell bark (EM!), secondary bark (GE). Cf.: I: phloem. Note! In German literature, rhytidome is referred to as 'Borke', which is linguistically close to bark. (2) all tissues outside the innermost phellogen. Syn.: outer bark (Fh!, REC, WS, Oul!, Nu!, IAWA!, Le!, BCFT2!, Wo, Th, Ry, Fo!, Wh2), bark (Ck, BM, Ro, Cha), true bark (PW!), dead bark (Wo, Ro, Le!, Ba, Po, Ji). (3) dead portion of the bark excluding lastformed periderm. Syn.: outer bark (Ho!). (4) superficial layer of the dead bark which detaches spontaneously (Tailfer 1989*). Comments: Definition (1) follows more or less closely Esau (1960), Martin & Crist (1970), and Fahn (1990). Definition (2) is more or less similar to that given by Chattaway (1953), BCFT2 (1957), Penford & Willis (1961), De Saint Aubin (1963), IAWA (1964), Den Outer (1967), Ford-Robertson (1971), Nultsch (1971), Ghouse & Jamal (1978), and Letouzey (1986). Definition (3) follows more or less that of SAF (1950), Bena (1960), Esau (1960), Howard (1971), and Trockenbrodt (1990), and definition (4) Troupin (1978). Rhytidome is composed principally of dead masses of cortical and phloem tissue in the young stems, and secondary phloem in the old stems. Thickness of the rhytidome Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka -- Macroscopic bark tenninology ------------------------- may be genetically controlled, or affected by the exposure to the sun or frequent fires. In addition, structure and proportion of tissues may vary during tree growth, and thus affect thickness of the bark. Diagnostic characters of the rhytidome are a rcsult of the weathering process, the tangential strain, the way of growing of the peridenn, the arrangement of the phellem, and the makeup and amount of tissues cut off by the peridenn from the bark. Typically, periderms are only thin layers in the former inner bark tissue, thus fonning only a small component of the whole outer bark. Occasionally periderm tissue dominates the bark (Quercus suber), or there is only just one or occasionally two superficial peridenns and therefore outer bark is absent or 1-2 mm thick (Fagus sylvatica; Whitmore 1963). Wood (1952) mentions the alternation of colour in bands formed by the usually darker peridenn layers and the lighter coloured secondary phloem, which sometimes occurs in species fonning successive periderms. Mostly, however, colour is unifonn or nearly so. 11 Bena (1960) applies a French tenn \~corce morte' in the sense of the definition (2), and restricts the term 'rhytidome' to the bark outside phellem. De Saint Aubin (1963) divides scaly or flaky rhytidome into two layers: outer rhytidome ('rhytidome externe') is a part which detaches easily when hit by a machete. The inner rhytidome ('rhytidome interne') consists of thin layers adherent to the tissues below. He adds that these rhytidome layers usually differ in colour. Srivastava (1964) remarks that rhytidome originates from the secondary phloem and, in such cases, may be considered merely a special tissue of the secondary phloem. Trockenbrodt (1990) proposes the replacement of the tenn outer bark by the unambiguous tenn rhytidome. However, also the tenn rhytidome is used in different senses. I accept the equivalent term outer bark for rhytidome, because both terms are common in present literature. Last-formed periderm should be noted, if there is a discernible colour difference. II. Bark texture (consistency) texture composition of the bark largely determined by the character of the cells composing the tissue, but also affected by the progress of decay of the rhytidome. Comments: The term texture is frequently used in wood, referring to its relative unifonnity to the touch or in the reaction to cutting tools. Here it is applied to bark consistency. Texture is often complicated by the presence and distribution of sclereids and fibres set in a parenchymatous matrix (Wood 1952). A rough distinction between the texture of outer bark and inner bark should be made when the blaze is examined. In addition, the quality of scales or flakes may be detennined. There is much confusion in tenninology and different categories of texture used by authors. It is next to impossible to present a list of tenns that are mutually exclusive. The texture may be described as fol.lows: corky: outer bark with the texture and quality of cork. Syn.: corky outer bark (WS). fibrous: outer and/or inner bark mainly composed offibres. Syn.: fibrous bark (Es3, Ss, Ro), shreddy bark (RDMB), fibrous flakes (Le). IneZ.: fibrous inner bark (WS). brittle: outer and/or inner bark is hard, breakable. Outer bark may emit a metallic sound on cutting, inner bark may be fibrous but still brittle (Wyatt-Smith 1954, Jimenez-Saa 1973). Syn.: crustaceous bark (Bo). IneZ.: brittle outer bark (WS), fibrousbreakable live bark (Ji), glass-breakable live bark (Ii), living bark with brittle fibres (Po). Downloaded from Brill.com01/25/2021 05:12:32AM via free access 12 IAWA Journal, Vol. 15 (1),1994 loose: outer and/or inner bark breaks up on cutting into coarse or fine grains (vs. firm). Syn.: crumbly bark (Ro). Incl.: granular flakes (Le), granular outer bark (WS), crumbly outer bark (WS), chunky inner bark (Wh2!). granular: usually referring to inner bark which is mainly composed of sclereids (Whitmore 1972). Cf: m.c: bark, stringy. mealy: outer bark falls off like powder (Rollet 1980). Syn.: mealy bark (Ro, Rt). Cf: m.c: bark, powdery. homogeneous: either fibres or sclereids occur (vs. heterogeneous) (Whitmore 1972). Note! Do not confuse homogeneous texture with homogeneous bark. soft: outer and/or inner bark is soft and easy to cut (vs. hard) (Wyatt-Smith 1954). Syn.: soft bark (Ro) (vs. hard bark (Ro, Rt), compact bark (BKl), stone bark (BM». Incl.: soft outer bark (WS), soft inner bark (WS) (vs. hard inner bark (WS». laminate: concentric, cylindrical or interrupted layers in the phloem formed by sclerenchymatic elements. Syn.: laminated bark (MW, Ro), laminated inner bark (WS), laminated live bark (Ii), long strings (of live bark) (Ji), several layers (Ji), layered pattern (in living bark) (Po). Incl.: superposed plates (Rt), tangential bands (Rt), concentric rings (Rt). Cf: lILa. ripple marks; L dilatation tissue. Comments: In addition to rhytidome, the development of phellem is stimulated by forest fires. Rollet (1982) observed very spectacular ridges, over 10 cm thick, in Caesalpinia coriaria, a species from Llanos. Sometimes corky outer bark may be easily detached by hand (Rollet 1982). Wyatt-Smith (1954) found corky texture in outer bark of Pithecellobium confertum. According to Wyatt-Smith (1954), barks with fibrous texture can often be peeled off in long strips in such trees as Aquilaria malaccensis and Artocarpus scortechinii. Esau (1969) mentions that the presence of fibres "induces the bark to split in a reticulate, or netted, pattern" (Acer platanoides, Juglans regia). Brittle texture may include both sclereids and fibres. Bor (1953), who used the term 'crustaceous' for the black, hard, gritty bark, and Wyatt-Smith (1954) found brittle bark common in Diospyros. In describing the loose texture authors have used many terms to describe the detaching of portions of the bark. Letouzey (1986) applies the term 'granular' to flakes or scales which break off easily. He gives examples like Milida excelsa (== Chlorophora) and Alstonia boonei. Wyatt-Smith (1954) mentions longitudinally broken, coarse granules, i. e. 'granular outer bark' in Shorea spp. He also limits the term 'crumbly' to outer bark which breaks in small particles on cutting, and gives the family Burseraceae as an example. Rollet (1982) applies the term 'crumbly' also to similar qualities of the phloem, as distinct from fibrous texture (for example most of the family Chrysobalanaeeae). However, he shows that the distinction between fibrous and crumbly inner bark is somewhat arbitrary because closer examination reveals merely sclereids and fibres in varying quantity. Roth (1981) characterises brittle and crumbly consistency, mentioning that it consists of "stone cell groups which separate easily from the surrounding parenchymatous tissue." She also stresses that the more advanced the progress of decay is in the rhytidome, the more crumbly and mealy it will be. Mealy texture can be detected by rubbing between fingers, for example in Chaetocarpus schomburgkianus (Rollet 1982). Homogeneous layers may be found in the phloem, although barks may be chiefly heterogeneous in texture. This should be noted from the blaze. Whitmore (l962a) found that smooth barks are fibrous inwards and granular outwards, and described the cause of this in terms of the great amount of tangential strain the smooth barks have to accommodate. The term 'soft' (vs. hard) texture should be restricted to an evaluation of cutting with reference to outer and! or inner bark, without regard to anatomical structure. Inner bark has Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology usually a yielding texture, often moist, for example in most Annonaceae. Wyatt-Smith (1954) mentions examples of soft outer bark, for instance certain Litsea spp., and Campnosperma auriculatum. Trees with hard texture in the bark occur in open and semideciduous forests affected by regular fires, but also in closed forests. The hardness of the rhytidome is variable, and depends on the amount of phellem and sclereids (Rollet 1982). Also special inclusions, such as Ca-oxalate crystals, in a large number may result in difficulty of cutting (Roth 1981). Bark may be so hard and resonant, for instance in Canarium resiniferum, that a clear ringing sound may be heard if struck with a smart blow with the back of a dao (= a large heavy knife used by the Burmese) (Bor 1953). Inner bark is hard and then usually dry, for example in lxonanthes icosandra (Wyatt-Smith 1954). Laminate texture refers to phloem where laminae are formed through dilatation tissue which contains sclereids in tangential layers. Wyatt-Smith (1954) and Whitmore (1962c) mention one example of such laminated inner -------------- 13 bark: Anisoptera spp. Jimenez-Saa (1973) distinguished three types of laminated texture, which are hardly applicable (see rejected terms). Roth (1981) elaborated a classification according to distribution of sclerenchymatic tissue, where sclerenchymatic tissue may be visible as superposed plates, tangential bands or continuous and concentric rings in the phloem structure. She also called these patterns 'hard bast types'. Concentric laminate structures are useful in describing a blaze in the field. For instance, Meijer & Wood (1964) identified layers of stone cells alternating with other layers of bark which they consider "a good character to distinguish some species of Dipterocarpaceae." The term laminate texture is related to the ripple marks, often meaning the same, but separated here, because in ripple marks rays are sometimes involved. Moreover, the term ripple marks is primarily used in describing tangential sections. Whitmore (1962a) distinguishes a laminated bark type in Dipterocarpaceae because of the laminated structure in the inner bark. See the definition in the list of rejected terms. III. Bark patterns III.a: Bark patterns in cross and tangential section corrugations the inner sUrface of the bark is corrugated matching the similar pattern on sapwood. Syn.: corrugated sapwood (Fs, Ro). Comments: De Rosayro (1953) and Jimenez-Saa (1973) used the term in this sense. When the bark is removed, one may see a wrinkled or corrugated sapwood surface like corduroy or the ridged formation of a washing board. It was found that large aggregate rays of the wood terminate in the indentations (Francis 1951). dilatation (growth) the process ensuring the tangential widening of the bark during growth (Trockenbrodt 1990*) (Fig. 2). See comments under I: dilatation tissue. flame-marks a pattern resembling flames formed by phloem rays seen in the cross section of phloem (Rollet 1982). Cf: lILa: phloem, scalariform. Comments: This is a variant of scalariform phloem. Rollet (1982) gives, among others, Anacardium giganteum and Scaphium macropodum as examples. phloem, mottled phloem which is marked with spots of various colours or shades in tangential section. Syn.: mottled inner bark (WS), mottled living bark (Po). Comments: Wyatt-Smith (1954) gives examples, such as Endospermum malaccense, and Polak (1992) Aspidosperma cruentum. No distinction is Downloaded from Brill.com01/25/2021 05:12:32AM via free access 14 IAWA Journal, Vol. 15 (1),1994 Fig. 2. Close-up of the blaze where dilation growth seen in the blaze of Catostemma fragrans, Guyana (photo A.M. Polak). - Fig. 3. Ripple marks in Tabebuia insignis var. monophylla, Guyana (photo A. M. Polak). made between tissues involved in mottled patterns. The term mottled is restricted to spots as seen in the blaze, and the term patchy to bark surface patterns. phloem, scalariform a pattern formed by phloem rays in the cross section of phloem resembling ladder-like structure with radial 'rungs' (Rollet 1982). Cf: lILa: flame-marks. Comments: This is the structure formed by phloem rays which separate other secondary phloem parts. Rollet (1982) gives a number of examples, for instance Scottellia coriacea and Khaya ivorensis. ripple marks fine, parallel, horizontal lines in the tangential section of wood or bark, caused by the storied structure of all the wood and bark elements, or by the distribution in horizontal layers of the wood rays and bark rays only (Voorhoeve 1965*) (Fig. 3). Cf : II: texture laminate; ill.a: streaks. Comments: BCFT2 (1957), IAWA (1964), Meijer (1974), and Panshin & De Zeeuw (1980) restrict the term to tangential and longitudinal surfaces of certain woods. Symington (1943) gave examples of diagnostic ripple marks in sapwood, viz. Hopea ferrea, Balanocarpus heimii (= Neobalanocarpus). Kunkel (1965) Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark tenninology ~----------~~--------~------------------------ uses it to describe horizontal lines in cambium (Stockwerkbau). Rollet (1982) compares it in his glossary with "markings similar to small ridges on the sand of the seashore." The tenn is close to the term laminate structure, but kept separate here because the tenn ripple marks has a broader definition which may be useful in describing wood characteristics in the blaze as well. streaks striations on the suiface of the blaze usually formed by phloem rays and sclerenchymatic tissues. Streaks may be: longitudinal: longitudinal strzatlOns against different-coloured background. Syn.: striated inner bark (WS), streaked inner bark (Ry), striped structure (Ro). reticulate: regular or wavy, net-like striations against a different-coloured background. Syn.: gritty inner bark (Ry), gridfibrous inclusions (Ji). Comments: De Rosayro (1953) applies 'streaks' only to longitudinal structures. He gives Wormia triquetra (= Dillenia) as an example, which has an appearance similar to coconut wood. Wyatt-Smith (1954) uses the tenn for radial stripes of a different colour, often white (Annonaceae). Apparently these are identical with phloem rays. Rollet (1982) mentions numerous examples, grouping them according to dominant colour of the tangential section. Reticulate patterns are fonned by phloem rays and tangential layers of phloem fibres. Rollet (1982) mentions, for example, Eschweilera corrugata (= Lecythis) and Terminalia superba. III. b: Fissuring bark, fissured (1) bark cracked lengthwise into fissures sep- arated by ridges. Syn.: striated bark (Ja, Ss, Ku), plated bark (RDMB). 15 (2) longitudinal grooves with width of the ridges between the grooves at least three times that of the grooves or fissures (Wyatt-Smith 1954*). (3) ridges separating fissures are twice or more times as wide as fissure (JimenezSaa 1973*). (4) longitudinal grooves with width less than flat-topped ridges separating them (Tailfer 1989*). Comments: In barks with successive peridenn fonnation, the expansion growth of the stem causes cracking of the rhytidome. More or less longitudinal ridges and grooves are fonned. Fissure formation depends on certain internal properties such as a fibrousness, ray dilatation, peridenn formation, etc. Irregular fissuring is often the result of fonnation of scales which shed only partly (Roth 1981). The bark should be studied in full-grown trees, otherwise results are not reliable. Definitions (2), (3), and (4) are very narrow. In addition to these, some other types of fissuration are described like 'fluted bark' (Wyatt-Smith 1954; followed by Den Outer 1972), and 'ridged bark' (see rejected tenns). The definition of ridged bark does not differ much from the term fluted bark which more likely seems to be just a variety of ridged bark. In literature the tenn 'fluted' is also applied to a stem, its characteristic shape is fonned by unequal secondary growth. De RosayrQ (1953) classified fissured bark into five types and some sub-types according to the closeness of fissures, ridges or the shape of fissures, and also the mode of cracking (with some examples). He does not name these types. Furthennore, Rollet (1980) distinguishes 'fine-fissured', 'coarse-fissured', 'deep-fissured', 'shallow-fissured' and 'wavy-fissured', but does not give any definitions. He suggests that a more refined classification of fissured barks should consider the width of ridges and grooves. The patterns of the outer surface of the bark are often extremely difficult to describe. Here, perhaps even more than with other features, authors use descriptive terms without defining them properly. Therefore much confusion and overlap exist. I recommend to deDownloaded from Brill.com01/25/2021 05:12:32AM via free access 16 IAWA Journal, Vol. 15 (1),1994 7 8 Figs. 4-9. Schematic drawings of different fissure and ridge types as seen in cross section. 4: Fissures are deep and ridges rounded. - 5: Fissures are shallow and irregular. - 6: Squareshaped fissures. - 7: Compound fissures. - 8: Flattened ridges. - 9: Hollow ridges. scribe fissures and ridges separately with measures of their average width. If used in the given sense, the descriptive terms accepted in the present paper should be sufficient. fissures: more or less longitudinal grooves between ridges in the rhytidome. They may be classified according to depth and length as follows: deep: at least as deep as half of the total thickness of the bark (Fig. 4). Syn.: deep-fissured bark (Ro, GJ, YYI), fissured bark (Po), furrowed bark (Ro!), deeply furrowed bark (Hi, REC), deeply cracked bark (Th), ridged bark (Ro!), rugged bark (Ro!), slitted fissuring (Ro), slotted fissuring (Ro). shallow: less than half as deep as the total thickness of the bark (Fig. 5, see also Figs. 6, 8, and 9). Syn.: shallow-fissured bark (GJ, YYI), shallow-furrowed bark (Hi), fine-fissured bark (Ra), scaly-fissured bole (Whl), cracked bark (Ro, Po, Ji), vertically cracked bark (WS), shallow-cracked bark (Th). boat-shaped: oval or elliptical fissures which are not continuous (Fig. lO). Syn.: boat-shaped fissured bark (WS, MW), vertical crevices (Le), boatshaped cracks (Ry). short: less than 15 cm long (WyattSmith 1954). long, elongated: more than 15 cm long (Wyatt-Smith 1954). In addition, fissures can be classified into different morphological types (see Whitmore 1962a, Yunus et al. 1990): V -shaped: more or less acute fissures sometimes penetrating inner bark, lined by special associated periderm( s) (See Fig. 4). Syn.: acute fissures (WS), V section fissures (Wh 1). round: the outer surface is concave in cross section (Wyatt-Smith 1954). square-shaped: flat bottom fissures, always restricted to the dead outer bark (Fig. 6). Syn.: square fissures (WS), square section fissures (Whl). Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka -- Macroscopic bark tenninology ----------------~-----------~~---------------------------------- irregular: different-sized gaps or furrows in the bark surface (Fig. 5). Syn.: irregular section fissures (Whl). compound: anastomosing shallow fissures which are formed in the bottoms of existing fissures (Fig. 7). Syn.: compound section fissures (Whl). wavy: longitudinal grooves that are coarse with wavy, more or less irregular faces difficult to define clearly (derived from De Rosayro [1953] and WyattSmith [1954]) (Fig. 11). Syn.: wavy fissured bark (WS, Ro), coarse fissured bark (Ro). Fissures may be: parallel: grooves are parallel, long, usually regular. The resulting, long ridges may crack transversally (De Rosayro 1953) (Fig. 12). oblique: grooves are short or long, anastomosing but not so regular and distinct as in reticulate fissured barks. The resulting ridges may crack transversally. reticulate: grooves join each other and divide again irregularly leaving non-continuous and sometimes obscure ridges. Cf: m.b: ridges reticulate; m.c: bark, tessellated. ridges: more or less continuous raised parts of the rhytidome between fissures. Ridges may be: flattened: the outer surface is plane in cross section (Fig. 8). hollow: the outer surface is concave in cross section (Wyatt-Smith 1954) (Fig. 9). Syn.: hollow-ridged bark (WS). rounded: the outer surface is convex in cross section (Fig. 4). V-shaped: the outer surface is sharp in cross section (de Rosayro 1953). reticulate: ridges join each other and irregularly divide again enclosing noncontinuous fissures (Wyatt-Smith 1954) (Fig. 14). Syn.: reticulate-ridged bark (WS), bark like stretched net (Le), interlaced strands (Ro), diamond-shaped pattern (Po). Cf: IILb: fissures reticulate. 17 Comments: The definitions of 'deep fissures' and 'shallow fissures' are followed more or less closely by Yunus et al. (1990). Wyatt-Smith (1954) and Rollet (1980) use the tenn 'cracked bark' which describes the bark that just begins to open. They divide cracked bark into 'grid-cracked' (~IILc: bark, tessellated) and 'vertically cracked bark'. These cracks, less than 1 cm wide, are continuous or noncontinuous. Whitmore (1962a) used the tenn 'scaly-fissured bole' to indicate the intennediate fonn between 'smooth' and 'shaggyscaly bole'. Moreover, he described bark types like 'deep fissured bark', and 'shallowfissured bark' (in Dipterocarpaceae), which are bark types as a whole. See the definitions in the list of rejected terms. Boat-shaped fissures are generally a sign of young barks, where cracks or fissures are just opening because of the tangential expansion growth of a stem. However, boat-shaped fissures can be deep. De Rosayro (1953) and Wyatt-Smith (1954) give Calophyllum spp. as examples. Wyatt-Smith (1954) classified grooves or fissures according to shape in cross section: shallow or deep, round (surface in form of hemisphere), acute (with converging faces), or square (with parallel faces). The terms 'coarse-fissured' and 'pitted bark' were used by RolIet (1982) in his glossary, but without a definition, however. Ridges may be described by their width, length, height or depth, shape, or the way they are sloughed. They may also fonn distinctive patterns, such as reticulation. Besides the use of shape and regularity, De Rosayro (1953) proposed to describe the distance between ridges (widely vs. closely spaced ridges). Hightshoe (1989) mentions, within the context of 'shallow-furrowed bark', that narrow ridges occur, for instance, in Liriodendron tulipifera, and wide ridges in iuglans cinerea. Ridges may also become cracked across into elongated, rectangular, platy segments coming close to tessellated bark. Wyatt-Smith (1954) gives an example of 'hollow-ridged bark', viz. Shorea leprosula. Downloaded from Brill.com01/25/2021 05:12:32AM via free access 18 IAWA Journal, Vol. 15 (1),1994 Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology I1I.c: Scaling bark, flaky; flakes (1) bark which has large and variable patches or flakes ofrhytidome, more than 7.5 cm long, which become detached (WyattSmith 1954*). Syn.: scale (Le!, Co!), sheet bark (BM), shaggy bark (Ro!), exfoliating bark (RDMB, Hi). IneZ.: ringed bark (RDMB). Cf: IILc: bark, scaly; III.c: bark, patchy; IILc: ring bark. (2) a bark with numerous very thin bark scales (Voorhoeve 1965*). (3) Meijer (1974) follows definition (2), but calls barks also flaky when "scales flake off". (4) ___ IILc: bark, scaly. (5) --- lILc: bark, patchy. Flakes may be (see also Rollet 1980, Letouzey 1986): rectangular. irregular. circular. papery: thin and very flexible flakes (vs. slab-like flakes). scrolled: long, thin flakes which are rolled up by their edges (Fig. 16). Syn.: scrolled bark (WS, Ro, Wh2), scroll-like dehiscence (Ry), peeling bark (Co, Kr, REC), horizontally I vertically exfoliating bark (Hi), minniritchi bark (BK2). shaggy: loosened, usually slightly curved rectangular or irregular flakes which may hang for a time on the stem (Whitmore 1962a) (Cf. Fig. 12). Syn.: shaggy bark (REC, Ro, Kr), flaky bark (Ro!), shaggy-scaly bole (Whl). Comments: Flakes are produced when bark develops large sheets of periderm that are intermediate in size between the parts shed in the cases of 19 ring bark and scaly bark. Whcn flakes are detached, a pattern of differently coloured areas may result. See III.c: patchy bark. De Rosayro (1953) uses 'flakes' for large rectangular pieces (Dipterocarpus zeylanicus), and 'scales' for small pieces like scales of fish (D. hispidus), but does not indicate the borderline between both terms. Letouzey (1986), and Corner (1988) use flakes interchangeably with scales. Polak (1992) originally follows De Rosayro's concept distinguishing flakes and scales, but he relates flakes to thickness of the stem. Hence a flake, with a size of 10 x 15 cm from a tree 0.2 m thick is regarded merely a scale on a tree I m thick. Relating the size of flakes to the thickness of stem may lead to confusion, though, since the thickness of the trunk will increase during the life-span of the tree. Wyatt-Smith (1954), Jimenez-Saa (1973), and Rollet (1980) recognise papery bark, with very thin pieces peeling off like paper. They do not indicate the size of the pieces of bark falling off. However, their examples, among others, Melaleuca leucadendron and certain Eugenia spp., suggest that in their publication, in fact, flakes are described. Hightshoe (1989) uses the term 'exfoliating bark' to describe thin or coarse strips, or sheets peeling either vertically (such as Thuja occidentalis), horizontally (Betula lutea =B. alleghaniensis). Brooker & Kleinig (1990b) describe 'minniritchi bark', which is a special type of eucalypt bark that is split both longitudinally and horizontally, the free edges of the flakes rolling back while still adherent to the trunk to uncover new green bark beneath. Rollet (1980) used the term 'shaggy bark' for Chlorophora excelsa (= Milicia) and Dipterocarpus sublamellatus. bark, heterogeneous more than one type of bark is encountered in the same stem (Fig. 13). Cf: II: texture heterogeneous. Fig. 10. Bark with boat-shaped fissures in Duguetia uniflora, Guyana (photo A.M. Polak). Fig. 11. Bark with developing wavy fissures in Bridelia micrantha, Malawi. - Fig. 12. Bark with parallel fissures in Terminalia amazonia, Guyana (photo A.M. Polak). - Fig. 13. Heterogeneous bark in Brachystegia boehmii, Malawi. Downloaded from Brill.com01/25/2021 05:12:32AM via free access 20 IAWA Journal, Vol. 15 (1),1994 Comments: Surface patterns of the stem may depend on the developmental stage of the bark. The appearance of bark from the base of the tree upwards may change considerably. I found a typical example in an African species, Brachystegia bussei, where scaly zones alternated with fairly smooth ones. bark, patchy lighter blotches on the outer surface of the rhytidome resulting from the irregular dehiscence of old rhytidome plates, usually two colours dominate on the bark (Rollet 1980, Letouzey 1986) (Fig. 18). Syn.: mottled bark (Ro), marble-like blotches (Le), blotched bark (Ja), spotted bark (Le), flaky bark (Kr!), patchy exfoliating bark (Hi). Comments: Kriissmann (1984) gives examples like Platanus, Acer, Stewartia, and Parrotia. The colour of patches where flakes or scales were recently shed, may give some additional information and should be reported with the use of colour charts. However, the differences in colour may be caused by lichens, especially on smooth barks. bark, powdery bark covered with a fine powder-like crust which usually rubs off easily. It is mostly associated with smooth barks (Wyatt-Smith 1954). Comments: This is a result of a usually long process of decay caused by weathering. Bor (1953) gives some characteristic examples, viz. Aporusa spp. and Bischofiajavanica. bark, scaly; scales (1) bark which has small more or less irreg- ular patches or scales of rhytidome, less than 7.5 cm long, which become detached (Wyatt-Smith 1954*). Syn.: scaly peeling bark (Th), flaky bark (Ti), alligator bark (Ir). Inc!.: ringed bark (RDMB). Cf: m.c: bark, t1aky; III.c: ring bark; IILc: bark, tessellated. (2) named after stem appearance when seen from a distance; fissures are squareshaped or irregular and scattered or close (seldom); the width of fissures is lO (25) mm, but they do not penetrate into the inner bark; sloughing of the bark is continual, usually in large scales up to c. 50 cm long, which are not formed in scollops: scales are elongate or isodiametric, layer-thick, loose or adherent, and occur scattered or in zones (abridged from Whitmore 1962a). (3) thin papery flakes separated by a mesh pattern of fine shallow vertical and horizontal fissures (Hightshoe 1989*). Scales: According to persistence one may roughly divide them as follows (see also Whitmore 1972): adherent: retained some time on the stem. loose-hanged: shed seasonally (Fig. 19, see also Fig. 13). Scales may be roughly divided according to density as follows (see also Whitmore 1972): close. distant. Scales may be roughly divided according to shape as follows (Whitmore 1962a, 1972, Rollet 1980, Letouzey 1986): rectangular. irregular. circular. papery: thin and very flexible. flat-sided: one or several layers thick. chunky: usually with irregular rough faces and irregularly chunky shaped. scollop-shaped: thickest in the middle, tapering to the edges, and leaving a scallop-shaped depression on the bole on sloughing (ef. Fig. 22). Syn.: plates (Ji). scrolled: thin scales which are rolled up by their edges. shaggy: loose and usually slightly curved, rectangular or irregular scales which may hang for a time on the stem (Fig. 19). Syn.: shaggy-scaly bole (Whl), shaggy bark (REe, Ro, Kr). Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology 21 Fig. 14. Bark with reticulate ridges in Fraxinus excelsior. - Fig. 15. Tesselated bark in Diospyros kaki. (Figs. 14 & 15 are redrawn from Vaucher 1990). - Fig. 16. Bark with scrolled flakes in Eucalyptus citriodora (redrawn from Thrower 1988). - Fig. 17. Bark with musselshell markings in Afzelia bracteata (redrawn from Voorhoeve 1965). Comments: Voorhoeve (1965) defines scales simply as "thin pieces of bark". According to Meijer (1974), scaly bark "can be dippled-scaly with oblong scales, or tessellate, like some species of Barringtonia." However, he calls bark 'flaky' when "scales flake off". Irvine (1952) has described very thick bark with large scales with the term 'alligator bark', for example in Butyrospermum parkii (= Vitellaria paradoxa). Roth (1981) does not distinguish scales and flakes, but instead uses the terms small and large scales. Definition (2) applies to a bark type of Dipterocarpaceae. See more details and drawings in Whitmore (1962a). For thc third definition Hightshoe (1989) gives Ostrya virginiana as an "indicator" species. Scaly barks vary much in detail. Many trees have fissured bark with scaly ridges, and in many cases one cannot distinguish between scaly barks and fissured barks, or scales are visible on ridges. Therefore it is practical to describe shapes of scales and fissures separately. Downloaded from Brill.com01/25/2021 05:12:32AM via free access 22 IAWA Journal, Vol. 15 (1),1994 Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology bark, stringy thick, loose, long-fibred bark, never deciduous (Penford & Willis 1961 *). Syn.: stripping bark (Co), fibrous peeling bark (Th), fibrous strips (Le). Cf: II: texture fibrous. Comments: This definition is followed more or less closely by Rollet (1980). Beard (1944) noted "ropy strings" in such species as Vitex divaricata and Citharexylum spinosum. The term has been applied, moreover, to certain roughbarked eucalypts. This texture arises, according to Chattaway (1953), through the expansion of the phloem parenchyma, separating bundles of fibres from one another in the rhytidome. Brooker & Kleinig (1990a) add that stringy bark is thick, spongy, deeply and widely furrowed, interlaced beneath, with outer layers weathered to grey or grey brown. This is a highly diagnostic feature. bark, surface rotten bark is shortly fissured (with fissures varying in depth and cross section), scaly, rugose or smooth; sloughing is very variable scales being small, adherent, chunky or flat-sided; in a transverse section the inner edge of the outer bark is following surface configurations, not parallel to cambium (Whitmore 1962a). Cf: III.b: bark, fissured (1); m.c: bark, scaly (1), (2); lII.c: bark, heterogeneous. Comments: A special type of the bark, which has a complex surface pattern. According to Whitmore (1962a), the thickness of outer bark and undulations of its inner edge are governed by the amount of rotting at the bark surface. Moreover, the periderms (if any) devel- 23 op as localised wound responses caused by insect of fungus attack. Bark has an appearance like rotting from the surface inwards, and there is a lot of variation in surface feature between trees and even parts of a tree. Whitmore (1962c) mentioned some Shorea species having this type of bark. bark, tessellated surface marked by more or less regular, square or oblong plates or blocks remaining for a long time on the stem (Fig. 15). Syn.: cracked bark (Co), reticulately scaly bark (Ss), grid-cracked bark (WS, Wh2, Ro, Ji), crocodile-skin bark (Bo), gritty bark (Po), blocky bark (Hi). Cf: III.c: bark, scaly; lII.c: bark, flaky. Comments: The definition follows more or less closely De Rosayro (1953), Hall et al. (1970) and Brooker & Kleinig (1990a). This is a special type of bark, where rhytidome blocks are usually retained. The rhytidome is short-fibred, breaking up into small plates. According to Brooker & Kleinig (1990a), plates may be hard and woody (in Eucalyptus, viz., paperfruited bloodwoods and some boxes), firm or spongy (in woody-fruited bloodwoods), and flaky (in yellow bloodwoods). The scales are usually thick and adherent. Wyatt-Smith (1954) applied the term grid-cracked to a special case of cracked bark with fissures which are just beginning to split, of which Rollet (1980) gives examples like achroma lagopus and Nauclea diderichii. I consider all these terms as synonyms for tessellated bark. Hightshoe (1989) mentions Diospyros virginiana as an "indicator" species of 'blocky bark'. Fig. 18. Patchy bark of Brachystegia bussei, Malawi. - Fig. 19. Bark with loose-hanged, shaggy scales in Pterocarpus rotundifolius var. polyanthus, Malawi. - Fig. 20. Rugose bark of Brachystegia glaucescens, Malawi. - Fig. 21. Smooth bark with lenticels in vertical lines (Ocotea tomentella), Guyana (photo AM. Polak). Downloaded from Brill.com01/25/2021 05:12:32AM via free access 24 IAWA Journal, Vol. 15 (1),1994 Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark tenninology ring bark (1) a type of rhytidome in which periderms may be formed parallel to the first one. The concentric cylinders of bark thus formed result in a rhytidome which detaches annually with large sheets (Esau 1960, Rollet 1980). Syn.: very smooth bark (Ro), smooth bark (BKl). Cf: scale bark, bark, peeling (1) (both in rejected tenns). (2) the outer bark when disengaged in strips or layers (Jackson 1928*). Comments: The rhytidome is shed annually, either once in a season or in several phases, and the resulting dead bark accumulates at the base of the trunk in certain trees (Brooker & Kleinig 1990a). The bark falls off in one piece or in large pieces or strips rolled up by their longitudinal edges (Rollet 1980). Srivastava (1964) has shown that if the first periderm was deepseated, the subsequent periderms follow the outlines of the external periderm, i.e., they encircle the axis and, consequently, form ring bark. Some barks are intennediate between ring bark and scaly bark, so outer layers of rhytidome are detached as relatively large flakes (for example in Platanus, Arbutus) (Esau 1965, Fahn 1990). Esau (1969) mentions that the bark detaches as flakes (Betula pendula), or as large plates (Platanus acerifolia) when sclereids are numerous. Usually fibres are then lacking or only scarce. Most barks are of the scale bark type with fissuring different from the rare ring bark type. The number of peridenns developed in the rhytidome, and their arrangement (parallel, or ramified and anastomosing) are decisive for scale formation; size, thickness, texture, shape, and outlines of the scales. Wood (1952) used the term 'peeling bark' for all kinds of deciduous barks. Roth (1981) proposes a new term for ring bark which is a literal translation of the Gennan word 'Ringelborke'. Her suggestion 25 is 'ring rhytidome' or 'annular rhytidome'. Nevertheless, ring bark is a well-established tenn, so the change of the tenn is not followed here. III.d: External markings bark, dippled (1) bark covered with shallow, usually circular depressions, more than 1 cm in diameter. These are scars of the scaledoff old bark (Wyatt-Smith 1954*) (Fig. 22). Syn.: jigsaw puzzle (like -) (Ro!,MW), dippled-scaly bark (Co). IneZ.: oyster shell markings (Ro). Cf: III.c: scales scollop-shaped; III.d: bark, pock-marked; HI.d: scroll marks. (2) named after stem appearance seen from a distance when the bark surface is dippled or smooth with scattered scollop-shaped scales and scroll marks; sloughing occurs as scollops, small ones being entire, large ones in pieces (abridged from Whitmore 1962a). Comments: Definition (1) is followed more or less closely by De Rosayro (1953) and Rollet (1980). Yunus et al. (1990) use the tenn when shallow depressions may be visible on the surface of the bark when slashed. JimenezSaa (1973) and Polak (1992) apply the tenn 'dippled' to more or less round depressions without distinguishing pock-marked bark from dip pled bark. Rollet (1980) employs the term 'oyster shell markings' describing depressions deeper than covered by the term dippled bark in the sense of Wyatt-Smith (1954), but here 'oyster shell markings' is included in dippled bark. Whitmore (1962a, 1972) uses the term in a slightly different meaning. According to him, the surface of a dippled bark is patchy in colour, sloughing off as small, round, usually close-set, scollop-shaped scales like in Pometia and Swintonia. The term 'dippled' (or more precisely Fig. 22. Dippled bark of Commiphora sp., Malawi. - Fig. 23. Bark with eye marks (Macaranga capensis), Malawi. - Fig. 24. Bark with ring-grooves (Myrica salicifolia), Malawi. Fig. 25. Prickles on the bark (Bombax malabaricum) (redrawn from Thrower 1988). Downloaded from Brill.com01/25/2021 05:12:32AM via free access 26 IAWA Journal, Vol. 15 (1),1994 'dippled-scaly') was originally introduced by Comer. According to him, 'dippled-scaly bark' has small, round, thin, and very numerous flakes looking like irregular discs which leave closely set scars on the bark surface (Melanorrhoea malayana = Gluta). The size and thickness of the scales, and colour of old and newly exposed surface may give some diagnostic information. It seems practicable to describe barks by the term dippled in combination with scroll-marks and pock-marked bark. bark, lenticellate; lenticels barks which have on the surface more or less raised, often somewhat corky spots or lenticels (Fig. 21). Syn.: pimpled (pimply) bark (Ro), pustulate bark (Vo, Ku, Ja). Here a combination of characters is presented which authors, as Wood (1952), Wyatt-Smith (1954), Rollet (1980), and Roth (1981), considered useful. Lenticels: The form of lenticels may be according to the greatest diameter: linear: usually horizontally elongated like buttonholes (rarely vertical). round: (usually small). stellate: star-shaped. diamond-shaped: rhomboid. The size of lenticels may be divided according to the greatest diameter (JimenezSaa 1973): large: more than 5 mm in diameter. medium: 3-5 mm in diameter. small: less than 3 mm in diameter. Lenticels may occur on bark: numerous (vs. scarce) (only when present in large numbers or only few). solitary (vs. compound). in vertical lines (Fig. 21). in horizontal lines. in oblique lines. According to their consistency they may be: soft. powdery. compact. Comments: Anatomically lenticels are structurally differentiated portions of the periderm which are characterised by a relatively loose arrangement of cells, where gaseous exchange takes place (Esau 1965). Their width varies from I mm to 10 mm (Comer 1988). Lenticels may persist for many years in barks with superficial periderm layers, like in Betula and Prunus avium, widening due to the thickening of the stem. On barks with successive periderm layers, however, the lenticels are difficult to notice in the fissures. On thick, homogeneous dead barks they tend to be lost, or at least are inconspicuous (Eames & MacDaniels 1947, Wood 1952). According to Busgen & Munch (1929), fissures of the bark usually initiate from the lenticels, as can be seen in Populus. Lenticels are good field characters for identification. Their size, colour, and density should be noted. A rough estimate, like numerous/scarce, is enough. However, they may occur relatively more abundantly on some parts of the bark than on others. UsualIy they are most conspicuous on young twigs. bark, pock-marked bark covered with small shallow circular depressions, less than I cm in diameter (Wyatt-Smith 1954*). Syn.: pock-marking (Wo), dimpled bark (Ss), eye-marked bark (Ro!), pock-pitted bark (Ro!), pitted bark (Vo, Dr), pitting (Wo!), spotted bark (Le). Cf: III.d: bark, dippled. Comments: De Rosayro (1953) reported this pattern (together with dippled bark) from a variety of Syzygium species. Pock-markings occur on the outer edge of the live bark (~ I: phelloderm). They affect the surface of the bark as seen on separation of the dead bark (Wood 1952). Meijer & Wood (1964) draw attention to this diagnostic feature describing it as a "bark with small irregular flakes and a rough appearance." Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology --------=---------------------------- bark, rough bark which has an uneven surface; the term includes various scaly, flaky and fissured barks. Cf: III.d: bark, rugose; III.d: bark, smooth. Comments: Wyatt-Smith (1954) has a similar definition. Rough bark patterns can be seen from a distance without closer inspection. bark, rugose (I) bark which is covered by wrinkles, depressions, small irregular scales, shallow fissures; bark appears smooth from a distance (Fig. 20). Syn.: wrinkled bark (Vo!, Rt), sculptured bark (Rt!), little rough bark (Le), smooth bark (WS, Ou2, Ry, Wh2), smoothish bark (Rt). Cf: IILd: bark, smooth; III.d: bark, rough. (2) small, medium or large, close or scattered lenticels or minute cracks (Whitmore 1972*). Syn.: firm bark (Dr). (3) covered with wrinkles, small depressions, furrows or ridges (Den Outer 1972*). Comments: The definition (I) is comparable with that by Roth (1981). Most rugose barks are thin. Whitmore's (1972) definition of rugose barks falls within his own circumscription of smooth barks. Roth (1981) also distinguishes fairly smooth or smoothish barks which "arise through exfoliating of the cork or through continuous desquamation of very small scales", but here they are considered rugose barks. Meijer & Wood's (1964) and Meijer's (1974) definitions of 'non-fissured bark' (see rejected terms) are close to rugose bark. Rugose appearance is a common feature in young developing barks, but the terminology is often obscure and difficult to interpret precisely from the context. bark, scribbly smooth bark carries characteristic 'scribbles' caused by insect larvae (Brooker & Kleinig 1990a*). 27 Comments: This condition may also be seen on the smooth upper trunk of a tree that has a rough bark on lower parts. The feature is diagnostic in some cases. bark, smooth (1) bark is even, thin, unbroken, though it may be bumpy or pimply from the lentieels (Corner 1988*) (Fig. 21). Syn.: close bark (Dr). Cf: III.d: bark, lenticellate; m.d: bark, rugose. (2) named after stem appearance seen from a distance; bark is thin (1-2 mm), usually without rhytidome; bark surface is entire, often with raised hoop and eye marks; sloughing is absent or inconspicuous with powdery appearance or tiny (1-2 mm) scales (abridged from Whitmore 1962a). (3) epidermis persistent, no outer layer of dead cells, surface smooth, no cracks or peeling (Thrower 1988*). (4) -7 IILd: bark, rugose (1). (5) -7 III.c: ring bark. Comments: The definition (1) is more or less similar to that by Radford et al. (1974), RoBet (1980), Kriissmann (1984), Letouzey (1986), Hightshoe (1989), and Yunus et al. (1990). Smooth barks may have hoops, eye-marks, prickles, and other types of excrescences, but not scales or fissures. Certain species may have the same appearance throughout the whole life of the tree, with lenticels and a unique periderm. A thin phellem layer may then cover the surface of the stem (Rollet 1980). The definition (2) is a description of a bark type of Dipterocarpaceae which was studied in detail by Whitmore (1962a). This corresponds well with the first definition, whereas Thrower (1988) in definition (3) applies the term only to the epidermis, for example in species of Ficus. Thus he does not apply the term to bark in the pure sense. Diagnostic characteristics, e.g. eye marks, prickles, etc. should be noted, although the bark is regarded otherwise as smooth. Downloaded from Brill.com01/25/2021 05:12:32AM via free access 28 IAWA Journal, Vol. 15 (1),1994 burls hard woody excrescences on a tree, more or less rounded inform, usually resulting from the entwined growth of a cluster of adventitious buds (SAF 1950*). Syn.: burr (Ja), gnaur (Ja). Cf: IILd: warts. Comments: The definition is more or less similar to that by Jackson (1928) and Sutton & Tinus (1983). Panshin & De Zeeuw (1980) describe it as "a bulge formed on the trunk or branches of a tree by abnormal wood formation." As some forest dictionaries give a wider definition for burr (see rejected terms), the term burl is preferred here. cankers (1) definite, relatively localised, necrotic lesions primarily of the bark and cambium (SAF 1950*). (2) ~ IILd: warts. Comments: The definition follows Jackson (1928) and BCFTl (1953) more or less closely. The term is confined to injuries or wounds of the bark without diagnostic significance. eye marks eye-shaped marks on trunks and branches of smooth-barked trees (Thrower 1988*) (Fig. 23). Syn.: hoops (Rt). Cf: III.d: hoops. Comments: Roth (1981), referring to eye marks as hoops, mentions that they mainly correspond to leaf scars or scars of lateral branches. As a result of expanding dilatation growth they partly or completely surround the stem. She considers that complete "hoops", i.e. eye marks, originate from decussate phyllotaxis, or from very broad leaf bases. Thrower (1988) follows this explanation. Whitmore (1962a) has a definition comparable with that by Thrower, but he suggests that the origin of eye marks is by the distortion of hoop marks formed on the stem. He adds that their distribution is too irregular for leaf scars, but they may sometimes be formed from branch scars. hoops (1) raised transverse rings which partially or completely encircle the stem (Cf. Fig. 24). Syn.: hooped bark (WS, Ro, Ry), horizontal rings (Po), hoop marks (Whl), ring-like marks (Ro). Inc!.: hoop-rings (Th), hooped bark (Ji), ring-hooped bark (Ji), horizontal folds (Le). Cf: IILd: ring-grooves. (2) ~ III.d: eye marks. Comments: Jimenez-Saa (1973) applies hooped bark to partial hoops and ring-hooped bark to complete hoops. Rollet (1980) does not distinguish hooped and ring-grooved bark in the text, although in his glossary he mentions two separate terms, viz. hooped and ring-like marks. Wyatt-Smith (1954) gives Sindora spp. as an example of hooped bark. These hoops usually occur on smoothbarked trees. Their origin is obscure, but, according to Thrower (1988), they are associated with eye-marks. Jimenez-Saa (1973) regards them as scars left by fused deciduous stipules. Whitmore (1962a) considers their distribution too irregular for leaf scars. mussel-shell markings parallel, sinuous, concentric ridges on the bark left after shedding of the rhytidome (Fig. 17). Syn.: parallel, sinuous ridges (Le). Cf: III.d: bark, dippled. Comments: This is a very conspicuous and diagnostic feature in some barks. Voorhoeve (1965) published a fine photograph of mussel-shell markings on the stem of Afzelia bracteata. Polak (1992) has found the character in Inga alba, and mentions it in the identification key on bark and slash characters, but he uses another term ('oyster shell markings') in the text, which is incorrect. Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark tenninology -------------------- prickles (1) sharp outgrowths from the bark, detachable without tearing the wood (Voorhoeve 1965*) (Fig. 25). Syn.: cork prickle (Rt). Cf.: m.d: spine. (2) ~ IILd: spine. See comments under spines. ring-grooves transverse grooves which partially or completely encircle the stem (Fig. 24). Syn.: ring-grooved bark (WS), rill (Ku). Cf.: IILd: hoops. Comments: The definition is similar to those of Kunkel (1965) and Radford et al. (1974). In one African tree, Myrica salicifolia, about 8 m tall, I found curious-looking ringgrooves, the bark exfoliating by small, irregular scales. Ring-grooves were densely distributed from the tree base up to the crown and branches. These grooves were fonned in the phloem, as the blaze did not show any grooves in the sapwood. I have not found any reports of this feature in literature about Myrica species. Wyatt-Smith (1954) mentions Shorea parvifolia as an example of ring-grooved bark. scroll marks raised sinuous marks between depressions which are formed when scollopshaped scales are detached (Whitmore 1962a) (Fig. 22). Syn.: scroll-marked bark (Wh2). Cf.: m.d: bark, dippled. Comments: The term 'scroll marks' is close to the tenn dippled bark. Whitmore (1962a) uses the tenn scroll-marked (bark) or scroll marks when speaking of smooth barks. This bark type is close to dippled bark. spines sharp hardened outgrowths of the bark and wood, usually modified branches or leaves; tearing the wood, if detached. 29 Syn.: thorn (Le!, Ro, Ja, Dr, RDMB, REC, Ti), prickle (WS). Cf.: m.d: prickle (1); excrescence, pointed (rejected tenn). Spines may be (Letouzey 1986): simple (vs. branched). straight (vs. curved). hard (vs. supple). tapering. conical. Comments: The distinction between non-woody 'prickles' and woody 'spincs' is followed by many authors. Defined in this way, they may have diagnostic value. Prickles occur in such species as Ceiba pentandra, Fagara macrophylla (= Zanthoxylum), Hura crepitans, and Jacaratia. Spines can be found for instance in Balanites wilsoniana, Bridelia grandis, Flacourtia rukam, and Cratoxylum formosum (Rollet 1980). Some authors do not make any difference between prickles and spines (Bor 1953). Roth (1981) describes pure cork fonnations or cork prickles originating from phellogen. Their appearance is variable, i. e. a roundish ring-like base with sharp-pointed end, or flattened. They may occur on the base of stem, on the upper side of twigs, sometimes densely crowded (Hura crepitans). Roth regards these as an excellent diagnostic character. However, De Rosayro (1953) does not rate occurrence of prickles or spines, although a notable character in trees of Ceylon, very highly, because this is mainly a juvenile feature. Wyatt-Smith (1954) defines prickles as similar to spines (stiff, sharp, woody, narrow, long processes), but thicker and wide-based. Besides 'thorn' Timberlake (1980) uses the tenn 'knob' for raised woody protuberances on a trunk, often with a thorn on top (Acacia). 'Pointed excrescences' (Letouzey 1986) resemble structures known as root spines! spine roots, which gradually develop into aerial roots with a sharply pointed apex, for instance in Bridelia micrantha and some palms (Jenik & Harris 1969). These spine formations are uncommon in dicotyledons, providing useful diagnostic infonnation, however, in certain cases. Downloaded from Brill.com01/25/2021 05:12:32AM via free access 30 IAWA Journal, Vo1.15 (1),1994 warts hard or firm excrescences other than lenticels, spines, prickles, or burls which are formed on the stem. Syn.: bumpy excrescence (Le), cankered bark (WS), verrucose bark (Ja!, HJC!, Vol). Cf: III.d: burls; III.d: bark, lenticellate. Comments: The definition is more or less similar to that by Jackson (1928) and Voorhoeve (1965). Warts may be, for instance, adventitious root buds which are just appearing on the main stem. Warts are distinctly smaller than burls which are usually formed by a cluster of adventitious buds. W. Exudation blaze, dry the surface of the blaze is not exuding, feels dry when touched. Syn.: dry live bark (Ji). blaze, wet the surface of the blaze slightly exuding, feels moistened when touched (Rollet 1980). Syn.: succulent live bark (Ji). Comments: When a blaze is wet, the exudate is usually a watery ooze from sieve elements. Note! The degree of wetness of the blaze depends partly on the season in which the bark is slashed. exudate moisture or liquid of the living tissue, which seep or flows after slashing, usually from the inner bark. Purely physically an exudate may be: clear: transparent (vs. opaque) (WyattSmith 1954). Examples (clear): Myristicaceae, certain Calophyllum spp. (Wyatt-Smith 1954). Examples (opaque): Artocarpus elasticus, certain Anacardiaceae (Wyatt-Smith 1954). coloured: may be white, yellow, golden, brownish, red, blackish. discoloured: the colour changes within a few minutes. frothy: forms foam when rubbed between fingers (Rollet 1980). liquid: flows readily, often transparent. Syn.: sappy exudate (Ku, Le, REC, Ja), watery exudate (WS,Ji). viscous: flows slowly, not necessarily sticky. Syn.: thick exudate (Ji). sticky: adhesive and sticks to the fingers (vs. non-sticky). Example (sticky): Hevea brasiliensis (Wyatt-Smith 1954*). odorous: smells pleasantly, for instance like incense or wintergreen (Rollet 1982). smelly: smells more or less unpleasantly, for instance like garlic, pepper, sulphur, excrement (Rollet 1982, Letouzey 1986). abundant: exudation is profuse for a while (vs. scanty). Cf: IV. blaze, wet. Comments: The definition more or less closely follows Wood (1952), Wyatt-Smith (1954), Den Outer (1972), Jimenez-Saa (1973), Rollet (1980), and Letouzey (1986). Certain families are characterised by their exudates (such as resin in Burseraceae). In other families different species may have their own type of exudate, or even certain species may show more than one type of exudate (Wood 1952). De Rosayro (1953) regards the nature and type of exudation "the most important single character of diagnostic value in identification." Some authors, e. g. Wood (1952), Rollet (1980, 1982), Letouzey (1986), have recommended that such diagnostic characters as a colour, discoloration, coagulation (both after few minutes exposure), smell, taste, speed with which it is oozed (in a continuous stream or in droplets), and how it is distributed in layers, should be noted in the description of exudates. However, Rollet (1980) values the colour of exudation most. Discoloration may also give useful hints for identification. De Rosayro (1953) has reserved the term 'watery exudate' for thin, clear or coloured Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka ~ Macroscopic bark terminology 31 --------------------------------------------~ exudates (see rejected terms). He gives examples of the red or reddish type, for instance Myristicaceae, and of the colourless type, for instance Campnosperma zeylanicum and Mangifera zeylanica. Wyatt-Smith (1954) defined the same term as an exudate resembling water (Antiaris toxicaria, Melanorrhoea = Cluta). I am inclined to refer to the exudate by its physical properties, e. g. colour, quality, etc., instead of using "traditional" terms like latex, resin, ctc. For instance latex is not always whitish, or resin brownish, and both include colourless types as well as gums. The chemical nature of exudates does not correspond well with the visual characterisation of traditional terms (cf. Hillis 1987). However, I accept some "traditional terms" because they are widely used, and, if defined properly, are descriptive to a certain degree. gum (I) viscid secretions, exuding naturally or on incision or infection, generally colourless, nontoxic, odourless, and usually tasteless; and on desiccation, or exposure to air, they become hard, clear, glassy masses (Hillis 1987*). Syn.: mucilaginous exudate (Ss, Ja), gelatinous exudate (Ja). (2) a comprehensive term for non-volatile, viscous exudates from many plants and trees, which either dissolve or swell up in contact with water; of complex chemical structure, they may be considered to be highly polymerised carbohydrates (BCFT2 1957*). Comments: The definition is similar to those given by Jackson (1928), Voorhoeve (1965), Den Outer (1972) and Rollet (1980). Hillis (1987) gives examples like Acacia and Sterculia. kino newly formed kino is usually of a thick consistency similar to that of honey, ranging from straw to blood-red in colour; ... and dries to a brittle, semi-transparent solid (Hillis 1987*). Comments: AHDE (1980) and BCFT2 (1957), when dealing with several Old World tropical trees, refer to kino as reddish resin. However, Hall et al. (1970) include it in gums which develop in the cambial region of Eucalyptus, often as a result of injury. The terms 'gum' and 'kino' are used indiscriminately in the literature as Hillis (1987) has pointed out. According to Hillis (1987), kino-bearing species are, for example, Butea frondosa (= B. monosperma), Pterocarpus marsupium, and some Eucalyptus species. He also mentions that appearance of kino may be characteristic of the species, and remarks that during spring and early summer it changes increasingly toward red. latex (1) latex is a colloidal suspension or emulsion of water-insoluble substances, suspended in an aqueous phase. It is typically white (milky), but may be yellow to red, or colourless (Hillis 1987). Syn.: lactiferous exudate (Ry). (2) the milky juice or exudate of certain plants: it is always opaque and of a white or yellow colour (Wyatt-Smith 1954*). Cf: exudate creamy (rejected term). Comments: Definition (1) is more or less similar to those given by Eames & MacDaniels (1947), Esau (1960), Jimenez-Saa (1973), and Comer (1988). Latex is found in a considerable number of angiosperm families, and is a source of many economic products. The suspensions may be of teipenoids (e.g. rubber), proteins, essential oils, mucilage, and other components (Hillis 1987, Eames & Mac Daniels 1947, Esau 1960). Comer (1988) regards it as very useful in the identification of many plants; it may change colour on exposure, its consistency being generally sticky, rubbery, resinous or gummy, but in some cases it is watery and even brown in colour. De Rosayro (1953) employs the term lactiferous exudate for an opaque and milky consistency. He distinguishes three categories of colour: (i) creamy or dirty white on exposure (for example Artocarpus spp.), (ii) pure white (majority of Sapotaceae), or (iii) coloured (Carcinia). Definition (2) is more or less similar to that used by Jackson (1928), SAF (1950), Downloaded from Brill.com01/25/2021 05:12:32AM via free access 32 IAWA Journal, Vol. 15 (1), 1994 BCFT2 (1957), .Kunkel (1965), Voorhoeve (1965), Den Outer (1967), Rollet (1980), Thrower (1988), and Tailfer (1989). According to Wyatt-Smith (1954), 'creamy exudate' (see rejected terms) occurs in Alstonia spp. and Sapotaceae. resin (1) colourless exudate or light brown glossy solids, which are stable, inert and amorphous and become sticky when heated (Hillis 1987). Hillis (1987) divides resins broadly into two main types: oleoresins: a solution of resin acids in turpentine; oleoresin is a pale yellow, clear and sticky mass, which upon evaporation of volatile compounds becomes brittle. Oleoresins exudes from the resin canals of wood and bark when exposed in conifers and Canarium luzonicum. 'natural resins': they can be colourless, as with dammars, or light brown glossy solids; they are stable, inert and amorphous, become sticky when heated and are fusible (above lOODC) with no sharp melting points. Resins or resin exudates that are stored on the hark or in cavities. They arc found in several genera of Dipterocarpaceae and Leguminosae/Caesalpiniaceae. Wellknown resins are dammars, copals (hard, from different genera, for example Copaifera spp.), elemis (soft, a numher of gen- era in Burseraceae), mastics (Pistacia lentiscus var. chios), and lacquer (Rhus vernicifera =R. verniciflua). (2) an exudate which is adhesive, clear and colourless, or pale yellow to dark brown or black in colour (dammar) (Wyatt-Smith 1954*). Syn.: resinous exudate (WS). IneZ.: resinous exudation (Ry), tarry exudate (Ry) (see rejected terms). (3) a thick, syrupy or gummy exudate of the bark, generally clear or slightly coloured: (i) yellow (Calophyllum), (ii) whitish or colourless (Canarium zeylanicum); both types are always accompanied by a strong aromatic scent (De Rosayro 1953). Cf: exudate tarry (rejected term). (4) very sticky sap, usually solidifying on exposure (Kunkel 1965*). Comments: The definition of oleoresin is more or less similar to that used by Jackson (1928) and BCFT2 (1957). Definition (2) is followed more or less closely by Den Outer (1972) and Rollet (1980), definition (3) by Iimenez-Saa (1973), and definition (4) by Storrs (1979) and Tailfer (1989). The main difference between these definitions is found in colour. De Rosayro (1953) distinguished also a 'tarry exudate' which is related to the definition (2) (see rejected terms). It is characteristic of the genus Semecmpus. Wyatt-Smith (1954) includes the tarry exudate in resin and gives Dipterocarpus spp. as an example. V. Bark cutting blaze (I) = slash a shallow Cllt removing a portion of'the bark and wood so as to aid ill species identification (Figs. 2 & 3). Syn.: slash (Vo. Ou2. Ku. Wh I, Wh2!, Le, WS, Woo Ry!, Ro!, BCFTI!. Bo!, Po!), cut (WS', Wh2', Ry', Ro', Bo!. Po'). q: IV: hlaze, dry/wet. (2) -'> I: hark, inner (3). Comments: The term has heen used in the first sense by SAF (1950), BCFTI (1953). De Rosayro (1953), and Rollet (1982). Originally 'slash' was used for "the bark slashed off by a cut", and the wound on a trunk, and especially the light coloured exposed sapwood was known as 'hlaze' (Wood 1952). A slash or hlaze reveals the eolour of the inner layers of hark, sapwood (hardwood) and exudate, a possihle discoloration when Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology exposed to the air, texture, smell, taste, etc. (Letouzey 1986). De Rosayro (1953), evaluating the nature of exudation as the most important and specific character of the blaze, points out that a blaze should be made on the stem and not on a buttress because of tissue differences. Letouzey (1986) mentions some other precautions to be observed when noting the appearance of bark: age of the tree, habitat of the tree, exposure of the bark, and the height at which the sample is taken. 33 slash (1) = blaze. (2) residual logging debris (SAF 1950, HeFTI 1953). Comments: Slash is accepted here as an alternative term for blaze. The term slash is commonly used also in this second sense. However, there is no danger of confusion. List of rejected terms bark, alligator bark, blocky IILc: bark, scaly. -7 -7 IILb: bark, tessellated. bark, blotched -7 IILc: bark, patchy. bark, cankered -7 m.d: warts. bark, chunky inner bark, close -7 -7 II: texture granular. m.d: bark, smooth (1). bark, coarse fissured fissures wavy. -7 III. b: bark, fissured, bark, cracked -7 IILb: bark fissured, fissures shallow; -7 m.c: bark, tessellated. bark, crumbly -7 -7 IILc: bark, tessel- II: texture granular. bark, crustaceous -7 II: texture brittle. bark, dead -7 I: rhytidome (2). - laminated, see I: periderm. bark, deep fissured - fissures are coarse and close; the size and section of fissures are very variable, but fissures do not penetrate into inner bark; ridges are flat-topped; sloughing occurs continually; chunky small scales (few cm) are adherent (abridged from Whitmore 1962a). See IILb: bark, fissured. bark, deeply cracked fissures deep. bark, deeply furrowed fissures deep. bark, dippled-scaly bark, - -7 -7 IILb: bark, fissured, III.b: bark, fissured, IILd: bark, dippled. -7 exfoliating horizontal -7 lILc: bark, flaky. vertical -7 lILc: bark, flaky. patchy -7 lILc: bark, patchy. bark, eye-marked marked. bark, fibrous inner bark, compact -7 II: texture hard. bark, crocodile-skin lated. bark, dimpled -7 m.d: bark, pock-marked. IILd: bark, pock- -7 -7 bark, fibrous peeling II: texture fibrous. -7 m.c: bark, stringy. bark, fine fissured -7 III. b: bark, fissured, fissures shallow. bark, firm -7 IILd: bark, rugose (2). bark, fluted - deep, continuous, round-bottomed longitudinal grooves with rounded ridges between them; width of ridge and width of groove approximately equal and total width more than 2.5 cm (Wyatt-Smith 1954*). See m.b: bark, fissured. bark, furrowed sures deep. -7 IILb: bark, fissured, fis- bark, granular outer bark, grid-cracked ed. bark, gritty -7 -7 -7 II: texture granular. IILc: bark, tessellat- lILc: bark, tessellated. bark, gritty inner -7 lILa: streaks reticulate. bark, hard -7 II: texture, hard; -7 I: phloem (with) sc1erenchymatic elements. Downloaded from Brill.com01/25/2021 05:12:32AM via free access IAWA Journal, Vol. 15 (1),1994 34 bark, hard inner --t II: texture hard. bark, hooped --t m.d: hoops. bark, inner - inner --t I: phloem, non-collapsed secondary phloem. - outer --t I: phloem, collapsed secondary phloem. bark, laminate - named after slash appearance; bark is scaly fissured; ridges are 2-6 cm wide with several unevenly overlapping flat layers; fissures are usually irregular in section, short; bark looks as though rotting from surface inwards; tissues loose, soft; in this type a sclerosis plays a role in which tangential sheets of sclerified tissues (close compound laminae) are formed to varying extent in the phloem proliferation tissue; layers can be seen in cross section (abridged from Whitmore 1962a). See II: texture laminate. bark, little rough -7 m.d: bark, rugose (1). bark, live - dry --t IV: blaze, dry. - fibrous-breakable -7 II: texture brittle. - glass-breakable -7 II: texture brittle. - inner layer (of the live bark) -7 I: phloem, non-collapsed secondary phloem. - laminated --t II: texture laminate. phloem contains very thin, flexible laminae of less than 1 mm; one can separate wide and and long laminae with fingers (Jimenez-Saa 1973). - (with) long strings -7 II: texture laminate. refers to laminae of live bark, which do not break easily and which can be pulled out as long strings, for instance in some species of Annonaceae and Lecythidaceae (Jimenez-Saa 1973). - (with) several layers --t II: texture laminate. laminae, which are not easily separable, and are in some cases about 2 mm thick (Jimenez-Saa 1973). - outer layer (of the live bark) -7 I: phloem, collapsed secondary phloem. - succulent --t IV: blaze, wet. bark, living - (1) the part of the bark outside the vascular cambium up to and including the last-formed periderm (Chan 1985*). See I: bark, inner. - (2) -7 I: bark, inner (3). bark, mealy -7 II: texture mealy. bark, middle - (1) in the phloem between inncr and outer bark, sometimes visible; it is the place where the division and differentiation of cells occur, and its relative thickness varies in the live bark depending on a species (Roth 1981 *). - (2) -7 I: phelloderm. bark, minniritchi scrolled. bark, mottled --t --t III.c: bark, flaky, flakes III.c: bark, patchy. bark, non-fissured - (1) bark is not fissured, but may still be cracked, flaky or pockmarked and not really smooth (Meijer & Wood 1964*). See m.d: bark, rugose. - (2) Totally smooth or scaly, or covered with lenticels (Meijer 1974*). Sce III.d: bark, rugose. bark, peeling - (1) all species with successive periderm layers show more or less peeling, from time to timc, of one or more cork layers; this may be haphazard, scasonal or controlled by external conditions such as frost, fire or insolation; ... form of peeling is directly related to mode of laying down of periderms (Wood 1952*). See scale bark (rejected terms); IILc: ring bark. - (2) -7 IILc: bark, flaky, flakes scrolled. bark, pimpled (pimply) cell ate. bark, pitted -7 bark, plated -7 -7 m.d: bark, lenti- IILd: bark, pock-marked. IILh: bark, fissured (1). bark, pock-pitted marked. -) IILd: bark, pock- bark, pustulate -) m.d: bark, lenticellate. hark, reticulately scaly -) IILc: bark, tessellated. Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - 35 Macroscopic bark terminology ------ bark, ridged - (I) deep continuous, longitudinal grooves often with flat-topped ridges between them: width of the ridge and width of the furrow approximately equal, and total width more than 2.5 cm; e.g. Shorea curtisii (Wyatt-Smith 1954*). See m.b: bark, fissured. - (2) -) IILb: bark, fissured, fissures deep. bark, spotted -) IILc: bark, patchy; -) IILd: bark, pock-marked. bark, ringed -) IILc: bark, flaky; -) IILc: bark, scaly split or cracked bark with circular fissures (Radford et al. 1974*). bark, striated inner -) I: phloem, phloem rays; -) III.a: streaks longitudinal. bark, rugged -) IILb: bark, fissured, fissures, deep. bark, stone -) II: texture hard. bark, streaked inner -) lILa: streaks longitudinal. bark, striated -) m.b: bark, fissured (1). bark, stripping -) m.c: bark, stringy. bark, true -) I: rhytidome (1), (2). bark, verrucose -) III.d: warts. bark, sculptured -) III.d: bark, rugose (1). bark, secondary -) I: rhytidome (1). bark, winged - bark with one or more thin, flat longitudinal expansions or elongate plates (Radford et al. 1974*). See m.c: bark, scaly. bark, shaggy -) IILc: bark, flaky; -) IILc: bark, flaky, flakes shaggy; -) IILc: bark, scaly, scales shaggy. bark, wrinkled -) m.d: bark, rugose (1). bark, shallow-cracked -) lII.b: bark, fissured, fissures shallow. bass -) I: bast (1); -) I: phloem fibre; -) I: phloem. bark, shallow-fissured - named after bole appearance from a distance; outer bark is a coherent mass united by periderms; V-section fissures are long and often penetrating into the inner bark; ridges are 25-50 mm wide and fissures about one-third of this; sloughing is infrequent, scales are to 5 x 15 cm in size, ridge-wide, layer-thick or chunky, and adherent (abridged from Whitmore 1962a). See IILb: bark, fissured. bast -) I: phloem fibre. - hard -) I: phloem, sclerenchymatic elements; -) I: phloem fibre. - primary -) I: phloem, primary phloem. - secondary -) I: phloem, secondary phloem. - soft, see I: phloem (note under sc1erenchymatic elements). bark, shallow-furrowed -) m.b: bark, fissured, fissures shallow. bast fibre -) I: bark fibre; -) I: phloem fibre. blaze -) bark, inner (3). bark, shreddy -) II: texture fibrous. bole - scaly-fissured -) IILb: bark, fissured, fissures shallow. - shaggy-scaly -) IILc: bark, flaky, flakes shaggy; -) m.c: bark, scaly, scales shaggy. bark, soft -) II: texture soft; see I: phloem (note under sc1erenchymatic elements). burrs - (1) lar$e excrescences on a tree trunk or major bnanch, and to the enlarged root bark, sheet -) IILc: bark, flaky. bark, shell -) I: rhytidome (1). Downloaded from Brill.com01/25/2021 05:12:32AM via free access 36 IAWA Journal, Vol. 15 (1), 1994 stock found in certain trees; the grain is highly contorted and presents a characteristic type of figure (SAF 1950, BeFTI 1953, and Ford-Robertson 1971). See m.d: burl. - (2) ~ III.d: burl. cambium - bark ~ - cork ~ - main ~ bium. :... wood ~ bium. I: phellogen. I: phellogen. I: cambium, vascular camI: cambium, vascular cam- cork - secondary ~ I: periderm (1). - spongy ~ I: phellem. cork prickle ~ cork skin I: phelloderm. ~ m.d: prickles (1). cortex - cork ~ I: phellem. - primary ~ I: cortex (1); ~ I: phloem, primary phloem. - secondary ~ I: phloem, secondary phloem; ~ I: phelloderm. cracks, boat-shaped ~ III.b: bark, fissured, fissures boat-shaped. crevices, vertical ~ III.b: bark, fissured, fissures boat-shaped. cut ~ V: blaze =slash. edge - inner: thin and often inconspicuous layer, which is the very young phloem and cambium of the current growing season (Wood 1952*). See I: cambium; I: phloem, non-collapsed secondary phloem. - outer ~ I: phelloderm. excrescences - bumpy ~ m.d: warts. - pointed: long, thick, woody outgrowth from the trunk (Letouzey 1986). See m.d: spines. expansion tissue ~ I: dilatation tissue. exudate - creamy - latex which is thick in consistency and opaque but not sticky (WyattSmith 1954*). See IV: latex (1), (2). - gelatinous ~ IV: gum (1). - lactiferous ~ IV: latex (1). - mucilaginous ~ IV: gum (1). - resinous ~ IV: resin (2). - sappy ~ IV: exudate, liquid. - tarry: black, tarry, acrid exudation, which is usually slow and appears initially as black dots or streaks which later coagulate; the stem often shows black, tar-like blotches on its exterior (De Rosayro 1953). See IV: resin (3). - thick ~ IV: exudate viscous. - watery: (1) thin, usually clean or resembling a solution of colouring matter in water which is subdivided into (i) red or reddish exudate, (ii) colourless exudation (De Rosayro 1953). See IV: exudate. (2) ~ IV: exudate liquid. fissures - acute ~ m.b: bark, fissured, fissures V-shaped. fissuring - slitted deep. - slotted deep. ~ m.b: bark, fissured, fissures ~ III. b: bark, fissured, fissures flakes - fibrous ~ II: texture fibrous. - granular ~ II: texture loose. folds, horizontal ~ gnaur ~ m.d: burl; hoop marks hoop-rings ~ ~ III.d: hoops. ~ burr (rejected terms). m.d: hoops. m.d: hoops. inclusions - fibrous ~ I: phloem, scIerenchymatic elements. Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology ---------------------- - grid-fibrous --7 III. a: streaks reticulate; --7 I: phloem, sclerenchymatic elements. - radial --7 I: dilatation tissue. - sandy --7 I: phloem, sclerenchymatic elements. - conducting --7 I: phloem, non-collapsed secondary phloem. - non-active --7 I: phloem, collapsed secondary phloem. - non-functional --7 I: phloem, collapsed secondary phloem. - non-functioning --7 I: phloem, collapsed secondary phloem. - non-conducting --7 I: phloem, collapsed secondary phloem. knob, see III.d: spines. layer - corky --7 I: periderm (1). - inner: corresponds to the younger phloem and rays without youngest phloem, which is a thin and often inconspicuous layer (Wood 1952). See I: phloem, noncollapsed secondary phloem. - outer: corresponds to the older phloem and rays with remnants of cortex and pericycle according to the age and species (Wood 1952). See I: phloem, collapsed secondary phloem. plates --7 IILc: bark, scaly, scales scollopshaped. - superposed --7 II: texture laminate. proliferation tissue, intercalary tion tissue. liber --7 I: phloem. - secondary --7 I: phloem, secondary phloem. --7 --7 rind --7 I: bark (1); --7 I: rhytidome (1). - inner --7 I: phloem. - outer --7 J: rhytidome (1) - primary --7 I: rhytidome (1). marks, ring-like --7 --7 m.d: bark, dip- II!.d: hoops. meristem - cork --7 I: phellogen. - lateral --7 I: cambium. pitting --7 --7 --7 m.d: hoops. I: phloem fibre. markings, oyster-shell pled. periblem I: dilata- m.d: ring-grooves. rings, horizontal liber fibre --7 ridges, parallel, sinuous, concentrical --7 m.d: mussel-shell-markings. rill leptome, see I: phloem (note under sclerenchymatic elements). 37 I: cortex (1). scale bark (1) a type of rhytidome in which the subsequent periderms develop as restricted overlapping strata, each cutting out a scale-like mass of tissue (Esau 1960*). See IILc: ring bark; II!.c: bark, flaky; IILc: bark, scaly; bark, peeling (rejected terms). (2) --7 I: rhytidome (1). stereome --7 I: phloem, sclerenchymatic elements. m.d: bark, pock-marked. phloem - functional --7 I: phloem, non-collapsed secondary phloem. - functioning --7 I: phloem, non-collapsed secondary phloem. structure, striped nal. thorn --7 wedges --7 lILa: streaks longitudi- m.d: spines. --7 I: dilatation tissue. Downloaded from Brill.com01/25/2021 05:12:32AM via free access 38 IAWA Journal, Vol. 15 (l), 1994 GLOSSARY OF THE SUGGESTED MACROSCOPICAL BARK TERMS I. Bark and its component tissues (Fig. 1) bark - all tissue outside the vascular cambium regardless of its composition. bark, inner = phloem. bark, outer = rhytidome. bark fibre - fibre in the bark. bast - any fibres of the outer part of the plant, though mostly obtained from the secondary phloem. cambium - a meristem with products of divisions arranged orderly in parallel files; consists of one layer of initials and their undifferentiated products, or derivatives. Applied only to the two lateral meristems: - vascular cambium: the meristematic cell layer responsible for the development of the wood and/or the phloem. - phellogen: the meristematic cell layer responsible for the development of the periderm. There are also other meristems which form additional tissues: - dilatation meristem: a radially oriented meristematic cell layer in the phloem ray of some plants; responsible for a distinctly funnel-shaped phloem ray dilatation. cork - a trade product which is mainly extracted from the cork oak tree (Quercus suber). cortex - the tissue of primary origin that belongs neither to the epidermis, the periderm, or the phloem; between epidermis (periderm) and the vascular system. dilatation tissue - all tissue affected by dilatation growth (Fig. 2). periderm - the secondarily developed protective bark tissue replacing the epidermis, or built during rhytidome formation; consists of phellem, phellogen, and phelloderm. ph ell em - a secondarily formed protective tissue in sterns and roots consisting of dead cells with chiefly suberised walls; developed outward from the phellogen and forming a part of periderm. phelloderm - a secondarily formed living tissfle developed inward from the phellogen, forming a part of periderm and resembling cortical parenchyma. phellogen, see under cambium. phloem = inner bark - a principal assimilate conducting tissue· composed of different tissues and usually located outward of the xylem and inward of the periderm. Phloem can be divided into: - primary phloem: phloem of primary origin. - secondary phloem: all bark tissues derived from the vascular cambium during secondary growth. Secondary phloem can be subdivided into two layers that are sometimes visible to the unaided eye: - non-collapsed secondary phloem: part of the secondary phloem with open and non-collapsed sieve-elements. - collapsed secondary phloem: part of secondary phloem where sieve elements, companion or Strasburger cells, and sometimes axial phloem parenchyma cells are collapsed Other structures in the secondary phloem that can sometimes be distinguished with the unaided eye: - sclerenchymatic elements: fibres, sclereids, and their intermediates forming various structures in the secondary phloem. Patterns thus formed may be seen in cross and tangential section. - phloem rays: rays traversing the phloem. phloem fibre - bark fibre of the phloem. Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark tenninology rhytidome = outer bark - the dead outer part of bark including the last-formed 39 periderm, cut off by this periderm from still living secondary phloem. II. Bark texture (consistency) texture - composition of the bark largely determined by the character of the cells composing the tissue, but also affected by the progress of decay of the rhytidome. The texture may be described as follows: - corky: outer bark with the texture and quality of cork. - fibrous: outer and/or inner bark mainly composed offibres. - brittle: outer and/or inner bark is hard, breakable. Outer bark may emit a metallic sound on cutting, inner bark may be fibrous but still brittle. -loose: outer and/or inner bark breaks up on cutting into coarse or fine grains (vs. firm). - granular: usually referring to inner bark which is mainly composed of sclereids. - mealy: outer bark falls off like powder. - homogeneous: either fibres or sclereids occur (vs. heterogeneous). - soft: outer and/or inner bark is soft and easy to cut (vs. hard). - laminate: concentric, cylindrical or interrupted layers in the phloem formed by sclerenchymatic elements. III. Bark patterns lILa: Bark patterns in cross and tangential section streaks - striations on the sUrface of the blaze usually formed by phloem rays and sclerenchymatic tissues. corrugations - the inner surface of the bark is corrugated matching the similar pattern on sapwood. Streaks may be: - longitudinal: longitudinal strzatlOns against different-coloured background. - reticulate: regular or wavy, net-like striations against different-coloured background. dilatation (growth) - the process ensuring the tangential widening of the bark during growth (Fig. 2). flame-marks - a pattern resembling flames formed by phloem rays seen in the cross section of phloem. phloem, mottled - phloem which is marked with spots of various colours or shades in tangential section. phloem, scalariform - a pattern formed by phloem rays in the cross section of phloem resembling ladder-like structure with radial 'rungs'. ripple marks - fine, parallel, horizontal lines in the tangential section of wood or bark, caused by the storied structure of all the wood and bark elements, or by the distribution in horizontal layers of the wood rays and bark rays only (Fig. 3). IILb: Fissuring bark, fissured - bark cracked lengthwise into fissures separated by ridges. fissures: more or less longitudinal grooves between ridges in the rhytidome. They may be classified according to depth and length as follows: - deep: at least as deep as half of the total thickness of the bark (Fig. 4). - shallow: less than half as deep as the total bark thickness (Fig. 5, see also Figs. 6,8, and 9). - boat-shaped: oval or elliptical fissures which are not continuous (Fig. 10). - short: less than 15 cm long. -long, elongated: more than 15 em long. Downloaded from Brill.com01/25/2021 05:12:32AM via free access 40 IAWA Journal, Vol. 15 (1),1994 In addition, fissures can be classified into different morphological types: - V-shaped: more or less acute fissures sometimes penetrating inner bark, lined by special associated periderm(s) (See Fig. 4). - round: the outer surface is concave in cross section. - square-shaped: flat bottom fissures, always restricted to the dead outer bark (Fig. 6). - irregular: different-sized gaps or furrows in the bark surface (Fig. 5). - compound: anastomosing shallow fissures which are formed in the bottoms of existing fissures (Fig. 7). - wavy: longitudinal grooves that are coarse with wavy, more or less irregular faces difficult to define clearly (Fig. 11). Fissures may be: - parallel: grooves are parallel, long, usually regular. The resulting, long ridges may crack transversally (Fig. 12). - oblique: grooves are short or long, anastomosing but not so regular and distinct as in reticulate fissured barks. The resulting ridges may crack transversally. - reticulate: grooves join each other and divide again irregularly leaving non-continuous and sometimes obscure ridges. ridges: more or less continuous raised parts of the rhytidome between fissures. Flakes may be: - rectangular. - irregular. - circular. - papery: thin and very flexible flakes (vs. slab-like flakes). - scrolled: long, thin flakes which are rolled up by their edges (Fig. 16). - shaggy: loosened, usually slightly curved rectangular or irregular flakes which may hang for a time on the stem (Cf. Fig. 12). bark, heterogeneous - more than one type of bark is encountered in the same stem (Fig. 13). bark, patchy -lighter blotches on the outer surface of the rhytidome resulting from the irregular dehiscence of old rhytidome plates, usually two colours dominate on the bark (Fig. 18). bark, powdery - bark covered with a fine powder-like crust which usually rubs off easily. It is mostly associated with smooth barks. bark, scaly; scales - bark which has small more or less irregular patches or scales of rhytidome, less than 7.5 cm long, which become detached. Ridges may be: Scales: - flattened: the outer surface is plane in cross section (Fig. 8). - hollow: the outer surface is concave in cross section (Fig. 9). - rounded: the outer sUrface is convex in cross section (Fig. 4). - V-shaped: the outer surface is sharp in cross section. - reticulate: ridges join each other and irregularly divide again enclosing noncontinuous fissures (Fig. 14). According to persistence one may roughly divide them as follows: - adherent: retained some time on the stem. -loose-hanged: shed seasonally (Fig. 19, see also Fig. 13). IIl.c: Scaling bark, flaky; flakes - bark which has large and variable patches or flakes of rhytidome, more than 7.5 cm long, which become detached. Scales may be roughly divided according to density as follows: - close. - distant. Scales may be roughly divided according to shape as follows: - rectangular. irregular. circular. papery: thin and very flexible. flat-sided: one or several layers thick. Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology - chunky: usually with irregular rough faces and irregularly chunky shaped. - scollop-shaped: thickest in the middle, tapering to the edges, and leaving a scollop-shaped depression on the bole on sloughing (Cf. Fig. 22). - scrolled: thin scales which are rolled up by their edges. - shaggy: loose and usually slightly curved, rectangular or irregular scales which may hang for a time on the stem (Fig. 19). bark, stringy - thick, loose, long-fibred bark, never deciduous. bark, surface rotten - bark is shortly fissured (with fissures varying in depth and cross section), scaly, rugose or smooth; sloughing is very variable scales being small, adherent, chunky or flat-sided; in a transverse section the inner edge of the outer bark is following sUrface configurations, not parallel to cambium. bark, tessellated - surface marked by more or less regular, square or oblong plates or blocks remaining for a long time on the stem (Fig. 15). ring bark - a type of rhytidome in which periderms may be formed parallel to the first one. The concentric cylinders of bark thus formed result in a rhytidome which detaches annually with large sheets. III.d: External markings bark, dippled - bark covered with shallow, usually circular depressions, more than 1 em in diameter. These are scars of the scaled-off old bark (Fig. 22). bark, lenticellate; lenticels - barks which have on the surface more or less raised, often somewhat corky spots or lenticels 41 - round: (usually small). - stellate: star-shaped. - diamond-shaped: rhomboid. The size of lenticels may be divided according to the greatest diameter: - large: more than 5 mm in diameter. - medium: 3-5 mm in diameter. - small: less than 3 mm in diameter. Lenticels may occur on bark: - numerous (vs. scarce) (only when present in large numbers or only few). solitary (vs. compound). in vertical lines (Fig. 21). - in horizontal lines. in oblique lines. According to their consistency they may be: - soft. - powdery. - compacted. bark, pock-marked - bark covered with small shallow circular depressions, less than 1 em in diameter. bark, rough - bark which has an uneven sUrface; the term includes various scaly, flaky and fissured barks. bark, rugose - bark which is covered by wrinkles, depressions, small irregularly desquamating scales, shallow fissures; bark appears smooth from a distance (Fig. 20). bark, scribbly - smooth bark carries characteristic 'scribbles' caused by insect larvae. bark, smooth - bark is even, thin, unbroken, though it may be bumpy or pimply from the lenticels (Fig. 21). Lenticels: burls - hard woody excrescences on a tree, more or less rounded in form, usually resulting from the entwined growth of a cluster of adventitious buds. The form of lenticels may be according to the greatest diameter: -linear: usually horizontally elongated like buttonholes (rarely vertical). cankers - definite, relatively localised, necrotic lesions primarily of the bark and cambium. (Fig. 21). Downloaded from Brill.com01/25/2021 05:12:32AM via free access 42 IAWA Journal, Vol. 15 (l), 1994 ------------------ eye marks - eye-shaped marks on trunks and branches of smooth-barked trees (Fig. 23). hoops - raised transverse rings which partially or completely encircle the stem (Cf. Fig. 24). mussel-shell markings - parallel, sinuous, concentric ridges on the bark left after shedding of the rhytidome (Fig. 17). prickles -- sharp outgrowths from the bark, detachable without tearing the woolf (Fig. 25). ring-grooves - transverse grooves which partially or completely encircle the stem (Fig. 24). scroll marks - raised sinuous marks between depressions which are formed when scollop-shaped scales are detached (Fig. 22). spines - sharp hardened outgrowths of the bark and wood, usually modified branches or leaves; tearing the wood, if detached. Spines may be: - simple (vs. branched). - straight (vs. curved). - hard (vs. supple). - tapering. - conical. warts - hard or firm excrescences other than lenticels, spines, prickles, or burls which are formed on the stem. IV. Exudation blaze dry - the surface of the blaze is not exuding, feels dry when touched. blaze, wet - the surface of the blaze slightly exuding, feels moistened when touched. exudate - moisture or liquid of the living tissue, which seep or flows after slashing, usually from the inner bark. Purely physically an exudate may be: - clear: transparent (vs. opaque). - coloured: may be white, yellow, golden, brownish, red, blackish. - discoloured: the colour changes within a few minutes. - frothy: forms foam when rubbed between fingers. -liquid: flows readily, often transparent. - viscous: flows slowly, not necessarily sticky. - sticky: adhesive and sticks to the fingers (vs. non-sticky). - odorous: smells pleasantly, for instance like incense or wintergreen. - smelly: smells more or less unpleasantly, for instance like garlic, pepper, sulphur, excrement. - abundant: exudation is profuse for a while (vs. scanty). gum - viscid secretions, exuding naturally or on incision or infection, generally colourless, nontoxic, odourless, and usually tasteless; and on desiccation, or exposure to air, they become hard, clear, glassy masses. kino - newly formed kino is usually of a thick consistency similar to that of honey, ranging from straw to blood-red in colour; . .. and dries to a brittle, semi-transparent solid. latex - latex is a colloidal suspension or emulsion of water-insoluble substances, suspended in an aqueous phase. It is typically white (milky), but may be yellow to red, or colourless. resin - colourless exudate or light brown glossy solids, which are stable, inert and amorphous and become sticky when heated. - oleoresins: a solution of resin acids in turpentine; oleoresin is a pale yellow, clear and sticky mass, which upon evaporation of volatile compounds becomes brittle. Downloaded from Brill.com01/25/2021 05:12:32AM via free access Junikka - Macroscopic bark terminology -'natural resins': they can be colourless, as with dammars, or light brown glossy solids; they are stable, inert and amorphous, become sticky when heated and are fusible (above JOO °C) with no sharp melting points. V. Bark cutting blaze = slash - a shallow cut removing a portion of the bark and wood so as to aid in species identification (Figs. 2 & 3). slash = blaze. Acknowledgements The author is greatly indebted to Jifke Koek-Noorman for the worthwhile discussions and her valuable advice concerning the structure of this article. I also thank Tim Whitmore, Pieter Baas, and an anonymous referee for their careful reading of the manuscript, and Lubbert Westra for correction of the English text. Thanks are due to Marcel Polak in Utrecht for permission to use his slides (Figs. 2, 3, lO, 12, 21). The author is also grateful to Henrik Rypkema for a schematic illustration of Fig. 1 and to Asko Nerg for the rest of the illustrations (Figs. 4-9, 14-17,25). Societas Biologica Fennica Vanamo and the Finnish Cultural Foundation provided financial support. References American heritage dictionary of the English language (1980). Houghton Mifflin, Boston. Beard, F. S. 1944. Key for the identification of the more important trees of Tobago on characters of bark and blaze. Empire Forest. J. 23: 34-36. Bena, P. 1960. Essences forestieres de Guyane. 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