Fleshy Fungi of New Brunswick >> Rhodocollybia unakensis

Rhodocollybia unakensis (Murr.) Halling

Scattered on dead wood (probably conifer) with brown rot, associated with Picea glauca, Betula papyrifera and Abies balsamea, Ragged Falls Flowage, Lepreau River, Charlotte Co., New Brunswick (12-10-03/02).

Bsidiospores pale orange yellow in spore print, dacryoid, smooth, occasionally dextrinoid in Melzer’s Solution above an unstained base, 6.0-7.9 (8.5) X 3.1-3.9 μm, Q = 1.66-2.39 (average[43]:6.9 X 3.4 μm, Q = 2.00). Cheilocystidia abundant and forming a continuous sterile margin, cylindrical to narrowly clavate. Pileipellis a cutis of narrow hyphae. Hyphae of pileal and lamellar trama conspicuously encrusted with annular bands of dark materrial.

Rhodocollybia unakensis, originally described from Unaka Springs, Tennessee, has been reported only rarely. Up until now, has not been found in New Brunswick, although previous reports from Massachusetts, North Carolina and Tennessee (Mycoportal) follow a familiar geographical pattern often including regions along the coast of the Bay of Fundy.

Rhodocollybia butyracea is a similar species that might be confused with R. unakensis, differing in its growth in soil and litter, rather than rotting wood, and in having lobed and branched cheilocystidia quite unlike those of R. unakensis. Some collections of R. lentinoides are also similar but have paler caps, smaller basidiospores and lack cheilocystidia altogether. All species of Rhodocollybia have at least some of their basidiospores dextrinoid in Melzer's Solution. Collection 12-10-03/02 had almost no dextrinoid basidiospores in the spore print but had a few when pieces of lamella were examined.

Photograph: D. Malloch (12-10-03/02).