SPECIES FACT SHEET
Common Name: Vezdaea lichen
Scientific Name: Vezdaea stipitata Poelt & Döbbeler
Division: Ascomycota
Class: Ascomycetes
Order: Lecanorales
Family: Vezdaeaceae
Technical Description: Thallus minute, green, crustose, growing on other
lichens (lichenicolous), hardly discernible, thin. Vezdaea grows under the
cortex of the host lichen or under the cuticle of moss leaves, then breaks
through the cortex or cuticle to form a visible thallus. Apothecia white, raised
on a short stalk or at least constricted below the apothecium, lacking a margin
and hypothecium, and short-lived. Paraphyses branched, rare (Coppins 1987),
asci and paraphyses not held in a gelatinous matrix. Asci thick-walled (2-3 µm)
but wall thinner at the apex; club-shaped. Spores 8 per ascus, (12.5) 13-15
(16) x 3-3.5 µm, hyaline, smooth, 1-septate, the two cells slightly different in
size. Photobiont Leptosira, a chlorococcoid genus of green algae occurring in
only a few genera of lichens. (Purvis et al. 1992; Poelt & Döbbeler 1975;
Tschermak-Woess and Poelt 1976.)
Chemistry: no lichen substances
Distinctive Characters: Very small, thin spots of green thallus on surface of
host lichen with tiny white, stalked, short-lived apothecia without margins,
spores 1-septate. Similar species: Two other species of Vezdaea are found in
North America, V. rheocarpa and V. leprosa. Neither of these taxa have stipitate
apothecia, and both can live on mosses or moribund lichens (Nash 2004).
Species of Micarea can grow on twigs and bryophytes as a thin thallus, and
have tiny (under 1 mm diameter) whitish apothecia, but the apothecia have a
proper margin, although it is often rudimentary and not easily seen, and asci
bound in gelatinous matrix. The thallus of Micarea does not develop under the
cuticle of the host, the walls of the asci are thinner (1-2 µm), and the
paraphyses do not form a network around the asci. Micarea stipitata has
stalked pycnidia and adnate white apothecia. Fellhanera bouteillei grows on
leaves in coastal and humid inland habitats, has tiny pinkish to white
apothecia 0.1-0.3 mm in diameter, with a proper margin, 1-septate spores with
one cell short and rounded, and the other longer and slightly narrower, making
the whole spore look like the footprint of a shoe. Other descriptions and
illustrations: Coppins 1987. Originally described and named by Poelt and
Döbbeler (1975).
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Life History: Vezdaea stipitata develops below the upper cortex of its host
lichen, then breaks through and grows on top (Tschermak-Woess and Poelt
1976). Scheidegger (1995) documented some aspects of the life history of
several Vezdaea species, but was not able to find thalli of V. stipitata on the
surface of the moss substrate, only beneath the leaf surface. He produced low
temperature scanning electron micrographs of the apothecia, which are shortlived and best collected in winter and spring. He also documented formation of
asexual propagules (conidia). This minute lichen has a high relative growth
rate, replacing its biomass approximately every three years, allowing it to grow
on decomposing substrates. It is essentially an emphemeral species, growing
fast and reproducing quickly in order to survive. Scheidegger (1995) concluded
that Vezdaea is rare, but by no means an endangered species in Switzerland.
On the contrary, in North America, where it colonizes lichen species that are
slow-growing and dependant on a very stable environment, it could be highly
vulnerable to changes in the habitat that eliminate the lichens on which it
lives.
Range, Distribution, and Abundance: Europe excluding Britain, and in the
Pacific Northwest of North America, where known only from two sites in
Oregon.
National Forests: none documented, suspected from lower elevations of the
Willamette, Umpqua, and forests within the Garry oak zone. BLM Districts:
documented from Roseburg District (Tater Hill RNA), suspected from Eugene
(adjacent to known occurrence near Marcola; Stone 1989) and Medford
districts.
This lichen is probably undercollected because of its miniscule size.
Habitat Associations: Growing on cyanolichens: Peltigera collina in Lane
County (Stone 1989) and Nephroma bellum in Douglas County (Stone, personal
observation). Both known sites are below 1500 ft elevation in habitats that are
very different: one is a grove of young Quercus garryana in a wet meadow, with
nearby Pseudotsuga menziesii. The other is a mixed riparian forest of Alnus
rubra, Tsuga heterophylla, Thuja plicata, Pseudotsuga menziesii and Acer
macrophyllum. Both sites have high humidity throughout the year, and at each
place Vezdaea was growing on twigs directly above water.
Threats: Vezdaea stipitata has been found only twice in Oregon, in humid
habitats near creeks. Narrowing buffers along creeks, thinning, and logging
lower humidity and can destroy habitat.
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Conservation Considerations: Relocate and monitor known sites. One site is
on private land not protected by federal land allocations. The other is within a
BLM ACEC. Search for new sites in protected areas such as federal riparian
buffers and state parks.
Conservation rankings: Global: G4; National: NNR; Oregon Natural Heritage
Information Center: List 3 (S1).
Preparer: Daphne Stone, with edits from John A. Christy
Date Completed: March 2009
Edits by: Rob Huff, BLM/FS, July 2009
References:
Coppins, B. J. 1987. The genus Vezdaea in the British Isles. Lichenologist
19(2): 167-176.
Nash, T. H., B. Ryan, P. Diederich, C. Gries & F. Bungartz. 2004. Lichen Flora
of the Greater Sonoran Desrert Region. Volume 2. Lichens Unlimited,
Arizona State University, Tempe, AZ. 742 pp.
Oregon Natural Heritage Information Center. 2007. Rare, threatened and
endangered species of Oregon. Oregon Natural Heritage Information Center,
Oregon
State
University.
Portland.
100
pp.
http://oregonstate.edu/ornhic/2007_t&e_book.pdf. Accessed 7 January
2009.
Poelt, J. & P. Döbbeler. 1975. Über moosparasitiche Arten der Flechten
gattungen Micarea und Vezdaea. Botansche Jahrbücher für Systematik,
Pflantzengeschichte und Pflantzengeographie 96: 328-352.
Purvis, O.W., B.J. Coppins, D.L. Hawksworth, P.W. James & D.M. Moore (eds.).
1992. The Lichen Flora of Great Britain and Ireland. Natural History
Museum Publications, London. 710 p.
Scheidegger, C. 1995. Reproductive strategies in Vezdaea (Lecanorales,
lichenized Ascomycetes): a low-temperature scanning electron microscopy
study of a ruderal species. Cryptogamic Botany 5(2): 163-171.
Stone, D. 1989. Epiphyte succession on Quercus garryana branches in the
Willamette Valley of western Oregon. The Bryologist 92(1): 81-94.
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Tschermak-Woess, E. & J. Poelt. 1976. Vezdaea, a peculiar lichen genus, and
its phycobiont. Pp. 89-105 in Brown, D.H., D.L. Hawksworth & R.H. Bailey.
Lichenology: Progress and Problems. Academic Press, New York. 551 pp.
Vezdaea stipitata,showing green patches of thallus and stipitate apothecia.
Photo by Daphne Stone, 2009.
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Nephroma sp. with Vezdaea stipitata. Area enlarged in upper photo
is at the center of the upper side. Photo by Daphne Stone, 2009.
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