Oligonema flavidum (Peck) Peck

Peck 1878: Annual Rep. New York State Mus. 31: 42
Basionym: Perichaena flavida Peck 1873: Bull. Buffalo Soc. Nat. Sci. 1: 65
Type loc.: USA, New York, Sand Lake.

Fructification
Sporocarps mostly gathered in close clusters, occasionally more scattered, sessile, short cylindrical to oblong pear-shaped, 0.7-1.5 mm high and 0.4-0.7 mm broad, bright yellow, shiny in RL, older sporocarps often somewhat ochraceous.

Peridium
membranaceous but rather robust, shiny, bright yellow in TL, on the inside with indistinct thin, short lines forming a whirl-like pattern reminding of a finger-print, occasionally with fine warts arranged in a similar pattern.

Capillitium
of free, tubular elaters, 4-5 µm broad, ca. 30-300 µm long, apices blunt, rounded, on the surface with a faint pattern of fine warts or short, transversal lines, bright (almost golden) yellow in TL.

Spores
spherical, bright yellow, pale yellowish in TL, with a, occasionally incomplete, net-ornamentation of 0.5-2 µm high ridges, 4-6 meshes across a diameter, the ridges themselves often composed of fine meshes, 9-10.4-12 µm Ø.

Ecology
Rotten wood of deciduos trees, among others Crataegus monogyna, mostly moist.

Distribution in Denmark
Rare, approx. 8 collections know.

Global distribution
Scattered in Western Europe, North Africa, scattered in Northern America.

Discussion
Macroscopically this species can hardly be separated from Trichia favoginea s.str. Micoscopically the two species are easily separated by the capillitium, which by O. flavidum is completely devoid of spiral ornamentation. In the field the the ecology may give a hint to the species: O. flavidum seems to occur almost exclusively in moist places, whereas T. favoginea is mainly found on rotten wood under drier conditions.

Description
Description and discussion based on Albertsen & Gøtzsche (1993).

 


Abbreviations: TL : transmitted light; RL : reflected light; Ø : diameter; TBU : Danish Botanical Topographical District.

Colour-codes refer to: Kornerup, A. & J. H. Wanscher 1974: Farver i farver. 5th reprint. Politikens Forlag, Copenhagen.

When not otherwise indicated spore measurements are given as: min-mean-max or (extreme-)min-mean-max(-extreme). Spore measurements are exclusive of ornamentation.

Line drawings are free hand sketches.

Distribution maps: Maps of Danish distributions are based on material seen by the author. World distributions are based on reports extracted from literature.