Jafnea semitosta
What You Should Know
Jafnea semitosta is an ascomycete (Pyronemataceae, Pezizales) originating from North America and spreading uncommonly in Europe. It is a fairly large cup fungus with a pale upper surface and an outer surface covered with fine brown hairs-rather like an overgrown version of the better known Humaria hemisphaerica.
Jafnea semitosta is a very variable species. Most authors stated the length of ascospores as 25–35 μm. The ascospores of some apothecia of our collection were mostly 27–29 μm long, only a few of them reached 30 μm, while those from other apothecia often surpassed 30 μm.
Jafnea semitosta Mushroom Identification
Ecology
Officially saprobic, but potentially mycorrhizal (in my view) like many members of the Pezizales; growing gregariously on the ground or from well-decayed wood; when terrestrial usually found near rotting wood, in lignin-rich soil; fond of conifer forests, but appearing under hardwoods as well; summer and fall; east of the Great Plains.
Fruiting Body
Deeply cup-shaped when young and usually retaining a cuplike shape into maturity; 1.5-7 cm across; upper surface bald and whitish, darkening to brownish with age; outer surface finely and sparsely hairy with brown hairs, pale brownish underneath the hairs; pseudo-stem usually present (but often buried), with a ribbed surface, up to 2 x 2 cm; flesh pale and brittle.
Spore Print
White.
Microscopic Features
Spores 25-35 x 10-12 µ; fusoid-ellipsoid; smooth in KOH, but warted in Melzer's reagent. Asci eight-spored; tips not bluing in Melzer's reagent. Paraphyses cylindric with rounded apices; yellowish in KOH; 2.5-7.5 µ wide. Hairs brown in KOH; septate; asperulate; up to 12.5 µ wide; apices rounded.
Jafnea semitosta Synonyms
Peziza hainesii Ellis, Bull. Torrey Bot. Club, 8 (6): 65 (1881), fide Durand (1906), Korf (1960)
Lachnea hainesii (Ellis) Sacc., Syll. fung., 8: 186 (1889)
Sources:
Photo 1 - Author: aarongunnar (Attribution 4.0 International)
Photo 2 - Author: alan_rockefeller (Attribution-ShareAlike 4.0 International)
Photo 3 - Author: aarongunnar (Attribution 4.0 International)
