The North American Species of Pholiota

118. Pholiota simulans sp. nov.

Illustrations: Text figs. 254-255; 256-258.

Pileus circa 8 cm latus, planus, squamullosus, subviscidus, griseobrunneus, sublutescens. Lamellae confertae, angustae, adnatae demum subdecurrentes. Stipes circa 8 cm longus, 9 mm crassus, subsquamulosus. Sporae 5-6 x 4-4.8 µ, leves, obscure truncatae. Pleurocystidia 36-54 x 8-13 µ, numerosa, fusoide ventricosa, ut chrysocystidia. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope Pontiac, Mich. 17 Sept. 1965, Smith 72658.

Pileus about 8 cm broad, plane with a decurved margin, or margin uplifted in age, surface covered by very fine appressed fibrillose squamules more numerous and less distinct over disc, squamules dull ochraceous tawny and disc this color from dense arrangement of squamules, becoming rimose toward margin, ground color with a yellowish tinge (more accentuated on drying), surface beneath the scales subviscid and soon dry. Context thin, buff, FeSO4 olivaceous; taste slight and not distinctive, odor none.

Stipe about 8 cm long, 9 mm thick, solid, equal, pale dingy greenish yellow with base dull clay-color, surface below veil-line decorated by fibrillose squamules or lacerate-fibrillose, pruinose above veil-line.

Spores 5-6 x 4-4.8 µ, smooth, apical pore distinct and larger spores obscurely truncate, in face view elliptic to subglobose, in profile about the same, pale dull tawny in KOH, paler in Melzer's reagent, wall about 0.25 µ thick.

Basidia 4-spored, 18-25 x 5-6.5 µ, subcylindric, pale ochraceous as revived in KOH or hyaline, appearing as if subgelatinous as revived in KOH (wall outline soon less distinct than walls of tramal hyphae). Pleurocystidia 36-54 x 8-13 µ, fusoid to fusoid-ventricose, the neck often drawn out to a crooked filamentose projection with a subacute apex; walls thin, smooth, hyaline; content showing a refractive-amorphous inclusion of various shapes and orange-brown in Melzer's reagent, sometimes the refractive body extending the length of the cell. Cheilocystidia versiform variable in size, the capitate cells with a head up to 12-15 µ and with the wall yellow as well as slightly thickened, otherwise thin-walled, hyaline and smooth. Caulocystidia numerous, versiform and variable in size, the large vesiculose cells up to 20 µ in diam., mostly with smooth hyaline thin walls; content homogeneous.

Gill trama of parallel smooth-walled hyphae the walls thin to slightly thickened, cells becoming inflated and greatly elongated; subhymenium cellular, of hyaline non-gelatinous hyphae. Pileus cutis with a thin pellicle of gelatinous to subgelatinous hyphae 2-4 µ, diam. and hyaline to yellowish in KOH, walls with incrusting plates of pale yellowish pigment; hypodermial region of floccose hyphae with some cells having slightly thickened walls but region not highly colored. Context of voluminous hyphal cells (12-30 µ) with "colloidal" content in KOH and bright orange in Melzer's reagent. Clamp connections present.

Habit, Habitat, and Distribution: Solitary on an old hardwood stump near Pontiac, Mich. Sept. 17, 1965, Smith 72658, type.

Observations: The fusoid chrysocystidia and the yellow-capitate cheilocystidia are an unusual set of features sufficient to distinguish a species. In the type of P. angustipes the cystidia are difficult to find and when found vary more to the clavate or filamentose condition. Overholts failed to note them.