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Plant Systematics - Fall 2001
Important Botanical Terminology
Vegetative Morphology
Duration
 annual: completes life cycle in one year
 biennial: completes life cycle in two years
 perennial: life cycle extends three or more years
 deciduous: plants which shed their leaves at the end of the "growing" season and become dormant
 evergreen: plants which remain green through the "dormant" season; never without leaves
 persistent: remaining attached
Habit (appearance)
 herbs: plants with non-woody stems
 arborescent: tree like
 shrub: woody perennial with more than one main stem
 tree: woody perennial with a single main stem
 vine: herbaceous plants with elongate, flexible, non-self-supporting stems
 liana: a woody vine
 caulescent: with an aerial stem
 acaulescent: more or less stemless
 climbing: climbs upon plants or other structures
 decumbent: stems on the ground but with tips turned up
 divergent: broadly spreading
 caespitose: growing in tufts or mats
 prostrate: lying flat upon the ground
 scapose: bearing the inflorescence on a leafless stem
 spreading: oriented outward from the point of origin
 twining: coiling around plants and other objects
Root System
 adventitious: roots which arise from any part other than the primary root system
 aerial: roots occurring above the ground
 fibrous: root system with all roots about the same size; no dominant root
 subterranean: underground roots
 tap: root system with one primary root
Stem Systems (aerial)
 stolon: horizontal stem, often rooting at the node
 tendril: a twining stem
 thorn: sharp pointed stem
Stem System (subterranean)
 bulb: upright series of overlapping, fleshy leaves separated by little or no internode
 corm: upright hard or fleshy stem surrounded by dry scaly leaves
 rhizome: horizontal stem with reduced scaly leaves
 tuber: enlarged, fleshy stem
Parts of the Leaf
 blade (lamina): flattened expanded portion
 petiole: stalk supporting the blade; absent in sessile leaves
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stipules: pair of appendages at the base of the petiole where it joins the stem
margin: the edge of the blade
node: point where the petiole attaches to the stem
internode: region of stem between consecutive nodes
Leaf Arrangement (phyllotaxy)
 alternate: one leaf per node
 opposite: two leaves at a node
 whorled: more than two leaves at a node
 basal: at the base of the plant
 cauline: leaves of a well-developed stem
 rosette: radiating cluster of leaves at the base of the plant
 distichous: two-ranked on opposite sides of the stem and in the same plane
Leaf Composition
 simple: blade composed of a single segment of tissue
 compound: blade divided into two or more distinct segments
 twice compound: blade divided into several distinct segmets branching from main rachis
 leaflet: segment of a compound leaflet
 rachis: central axis of a compound leaf
 fascicled: clustered, in a bundle
Leaf Venation
 net (reticulate): major and minor veins form a complex network
 palmate: major veins radiate from a central point at the bottom of the blade
 parallel: several veins of approximately the same size running parallel to one another
 pinnate: predominant midvein with minor veins arising along its length
Leaf Modifications
 bract: modified leaf often associated with a flower or inflorescence
 sheath: basal portion of leaf that surrounds the stem
 spine: sharp pointed leaf or portion of a leaf
 tendril: twining leaf or portion of a leaf
Leaf Surface Features
 glabrous: without hairs
 glaucous: covered with whitish waxy material
 viscid: sticky
 lustrous: shining
Vesture (vestiture): trichome coverings
 glandular: hairs with swollen tips
 pubescent: downy with short, soft hairs
 scabrous: rough with coarse, stiff hairs
 tomentose: densely covered with soft hairs
 villous: long, soft hairs, shaggy but not matted
 hispid: rough, stiff hairs
 stellate: hairs with many arms branching frm a central point or stalk
 hirsute: rough or coarse, more or less erect hairs
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Shapes
 cordate: shape like a heart on a valentine
 deltoid: shape of a Greek D, equilateral triangle
 lanceolate: shaped like the tip of a lance, several times longer than wide with curved sides, widet point at
base where petiole or otehr structure attaches
 reniform: kidkey shaped
 sagittate: arrowhead shape
 ovate: shape similar to the longitudinal section through a chicken egg, widest point at base where attached
to petiole or other structures
 ob-: suffix refering to structure (e.g., leaf) attaced at narrowest point. (e.g., oblanceolate)
Margins
 ciliate: with fine hairs along margin
 dentate: angular teeth with points directed away from the margin
 serrate: coarse teeth like a saw, points curved forward
 undulate: wavy
 entire: no indentation
 revolute: margin rolled towards the center of the plane of the blade
Apex and base
 acute: margins meeting at less than 90o angle
 obtuse: margins meeting at greater than 90o angle
 attenuate: long and tapering
 rounded: gently curved
 truncate: chopped off appearance
 caudate: tail-like
 auriculate: with lobed resembling the lobe of a human ear
 saggitate: arrowhead shaped and pointing away
 hastate: arrowhead shaped with lobes diverging
 oblique: asymmetrical, unequal-sided
Floral and Fruit Morphology
General Terms
 sepal: outer series of sterile appendages; often green
 petal: inner series of sterile appendages; often colored
 tepal: term applied when tepals and petals are not readily differentiated
 calyx: floral series composed of sepals
 corolla: floral series composed of petals
 perianth: calyx and corolla
 receptacle: stem tip where floral series are inserted
 stamen: pollen producing reproductive structure
 carpel: ovule producing reproductive structure
 androecium: floral series composed of stamens
 gynoecium: floral series composed of carpels
Presence or Absence of Floral Series
Floral Level
 complete: flower with all four series
 incomplete: flower with one or more series missing
 perfect: (bisexual): flower with stamens and carpels
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 imperfect: (unisexual): flower missing stamens or carpels but not both
 staminate: unisexual flower without carpels
 pistillate: unisexual flower without stamens
Plant Level
 hermaphroditic: plant with perfect flowers
 monoecious: plant with staminate and pistillate flowers
 dioecious: plant with staminate or pistillate flowers only
Insertion of Floral Parts Relative to Gynoecium
 hypogynous: sepals petal & stamens inserted below the ovary
 epigynous: sepals petal & stamens inserted above the ovary
Position of Gynoecium Relative to Floral Parts
 superior: gynoecium above floral parts
 inferior: gynoecium below floral parts
Fusion of Parts
 apo-: with separate parts (e.g. apopetalous: with separate petals)
 connate: fusion of like parts
 syn-: with fused sepals (e.g., sympetalous: with fused petals)
Floral Symmetry
 actinomorphic (radial, regular): sepals and petals radiating from the center of the flower
 zygomorphic (bilateral): perianth constituted such that only a median section yields two equal halves
Androecium
 anther: pollen producing structure
 filament: stalk supporting the anther
Gynoecium
 stigma: pollen receiving area
 style: "neck" shaped area below stigma
 ovary: seed bearing area beneath style
 unicarpellate: gynoecium composed of a single carpel
 placenta: region where ovules are attached
 locule: chamber within the ovary
 ovule: immature seed
 septum: interior wall separating locules
Inflorescences
 inflorescence: arrangement of one or more flowers on a floral axis
 involucre: organized set of bracts
 pedicel: supporting stalk of an individual flower in a multi-flowered inflorescence
 peduncle: supporting stalk of a multi-flowered inflorescence or a solitary flower
 rachis central axis of an inflorescence
 sessile: lacking a pedicel
 scape: leafless flowering stalk
 solitary: single flower on a flowering stalk
 axillary: flower arising from the axil of a leaf
 terminal: at the apex of the flowering stalk
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raceme: pedicellate flowers on an unbranched rachis
umbel: pedicels arise from the apex of the peduncle
panicle: central rachis is branched as may be the branches
spike: flowers sessile on rachis
Fruits
 fruit: ripened ovary and its contents
 dehiscent: fruit which opens by sutures, pores, or caps
 indehiscent: fruit which does not open
Dry Fruits
 achene: seed and pericarp (sunflower seed)
 samara: winged achene (maple seed)
 nut (i): derived from syncarpous gynoecium; one seeded; hard exocarp (walnut, pecan, acorn)
 capsule (d): derived from syncarpous gynoecium; many seeded (yucca, okra)
 follicle (d): unicarpellate, dehiscing along one suture (milkweed)
 legume (d): unicarpellate: dehiscing along both sutures (bean)
Fleshy Fruits
 drupe: exocarp a "skin", mesocarp fleshy; endocarp bony (peach)
 berry: entire pericarp soft (tomato, grape)
 pepo: berry with a leathery rind (squash, watermelon)
 pome: ovary surrounded by a fleshy tissue (apple)
 hesperidium: thick rind; conspicuous septation (citrus fruit)