The North American species of Pholiota, by Alexander H. Smith and L. R. Hesler.

Smith ~ Hesler

225

Hypodendrum adiposum (Fr.) Overholts, North Amer. Fl. 10: 279. 1932.
Illustrations: Text figs. 245-247.
Pileus caespitose, 6-9 (16) cm broad, convex, then plane, yellow to
dark-yellow, viscid or glutinous, with ferruginous-brown, more or less
concentric scales, which dry down to resemble cherry-gum. Context yellow.
Lamellae adnate to sinuate, at first yellow or straw-yellow, becoming
ferruginous, close, broad.
Stipe 5-12 cm long, 6-15 mm thick, viscid or glutinous, yellow
above, becoming ferruginous brown downward, base enlarged, with
numerous, glutinous, superficial squarrose or recurved scales up to the
apical ring. Inner veil yellowish, subfloccose, forming an evanescent
annulus.
Spores 5-6 X 3-4,i, smooth, with a minute apical pore; shape in
face view ovate to elliptic, in profile subelliptic to slightly bean-shaped;
color in KOH pale tawny to clay-color, in Melzer's merely ochraceous;
wall thin (-0.25 /z).
Basidia 16-20 X 3.5-5 J,, 4-spored, narrowly clavate, hyaline in KOH,
weakly yellowish in Melzer's reagent. Pleurocystidia of two types: 1)
25-40 x 5-10 u, subfusoid, walls thin smooth and hyaline, content
coagulated and shrunken away from the walls, wrinkled, dark brown in
KOH and in Melzer's reagent: 2) chrysocystidia 18-28 (33) x 6-9 (13) M/
fusoid to somewhat fusoid-ventricose; walls thin, smooth and hyaline;
inclusion small, hyaline in KOH and Melzer's reagent, usually well defined. Caulocystidia none except for those in the caulohymenium at very
apex of the stipe and resembling hymenial cystidia.
Gill trama a floccose central area of somewhat interwoven hyphae
hyaline in KOH, the cell walls thin and smooth; subhymenium a thin
gelatinous layer of very narrow hyphae. Pileus cutis a very thick gelatinous pellicle of yellow to cinnamon-colored hyphae 2-5 /L diam., collapsing,
walls mostly smooth. Clamp connections present. All hyphae inamyloid.
HABIT, HABITAT, AND DISTRIBUTION: On hardwood logs, British
Columbia. September.
OBSERVATIONS: This species has been misinterpreted by some European mycologists, and even to a greater extent in North America. We are
following the concepts of Lange, Ricken, Kuhner 8c Romagnesi, Moser
and Reid, all of whom appear to agree that its distinctive characters are
a viscid or slimy pileus yellow to dark yellow with brown scales which
become cherry-gum-like, viscid or slimy scales on the stipe, and spores
5-6 x 3-4 L,. This species has obviously been confused with P. aurivella,
which also has broad gills, but has a dry stipe, and larger spores than
P. adiposa. Many of the North American collections, in various herbaria,
are filed erroneously under one of these names. The true P. adiposa
appears to be rare in North America. The microscopic data given in our
description are taken from a collection by Derek Reid at Oldbury.