The North American Species of Pholiota

193. Pholiota macrocystis sp. nov.

Illustrations: Text figs. 434-435, 437-439.

Pileus 4-8 cm latus, late contextus, glaber, viscidus pallide argillaceus. Contextus crassus, pallidus tactu argillaceus. Lamellae latae, confertae, subcinnamomeae. Stipes 3-7 cm longus, 7-10 mm crassus, intus subargillaceus, extus albidus. Sporae 5.5-6.5 (7) x 4-4.5 µ. Pleurocystidia 60-104 x 7-12 (16) µ, fusoide ventricosa. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope Lake Fork Creek, Payette National Forest, Idaho. 29 Juni 1962, Smith 65070.

Pileus 4-8 cm broad, broadly convex to plane, viscid, glabrous, "pinkish-buff," youngest pale pinkish buff. Context thick pallid; odor and taste mild. With FeSO4 greenish, with KOH dark brownish; slowly staining cinnamon-buff when cut.

Lamellae adnexed, broad, close, pale cinnamon-brown mature.

Stipe 3-7 cm long, 7-10 mm thick, pinkish-buff, cortex watery cinnamon buff, surface white and unpolished, with a faint zone of fibrils from the thin veil, pith silky and pallid.

Spores 5.5-6.5 (7) x 4-4.5 µ, smooth, apical pore (for all practical purposes) none; in shape elliptic to ovate in face view, in profile obscurely bean-shaped to obscurely inequilateral; color dull cinnamon in KOH, pale and more ochraceous in Melzer's reagent, wall thin (less than 0.2 µ by estimate).

Basidia 20-25 x 6-7 µ, 4-spored, clavate, hyaline to yellowish in KOH, more yellowish in Melzer's reagent. Pleurocystidia 60-104 x 7-12(16) µ, fusoid ventricose with apex obtuse, often constricted at base of neck, neck 30-50 µ long, occasionally capitate, thin-walled, content homogeneous or with some rod-shaped debris in neck near apex, hyaline to yellowish in KOH. Cheilocystidia 40-77 x 8-12 µ, similar in shape to pleurocystidia. Caulocystidia 53-110 x 9-15 µ versiform-cylindric, subclavate, ventricose rostrate to fusoid-ventricose, or variously shaped, wall thin, and smooth, content homogeneous.

Gill trama of parallel hyphae with elongate cells 6-12 µ or more broad, walls thin, smooth more or less ochraceous in KOH; subhymenium cellular, the layer thin and inconspicuous, rather translucent in old gills. Pileus cutis a hyaline gelatinous pellicle, the hyphae 2-4 µ diam., walls thin smooth and in age only the refractive cross wall showing; hypodermium of smooth orange-brown hyphae 4-12 µ diam., non-gelatinous. Context hyphae of inflated cells with thin smooth walls pale tan in KOH becoming paler on standing. Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: On a conifer log, McCall, Idaho, June 29, 1962. Smith 65070, type.

Observations: The pinkish buff (not truly yellow) pileus, the green FeSO4 reaction, very large distinctly thin-walled pleurocystidia, essentially cellular subhymenium, context staining when cut, and relatively broad spores for their length are distinctive. It is an odd combination to have such pleurocystidia with the thin cellular subhymenium.