The North American Species of Pholiota

82. Pholiota flavescens sp. nov.

Illustrations: Text figs. 113-116.

Pileus 1-4 cm latus, convexus, albidus demum pallide luteus, vel flavidus, saepe ad marginem luteo-olivaceus. Lamellae subdecurrentes, pallide Iuteae, confertae, latae. Stipes 2-4 cm longus, 2.5-4 (8) mm crassus, sursum albidus, deorsurm sordidus, fibrillosus. Sporae 5.5-7 (7.5) x 3.5-4 µ. Chrysocystidia rara 22-30 x 5-8 µ. Caulocystidia versiformia. Specimen typicum in Herb. Univ. of Tenn. conservatum est; legit prope Gatlinburg, Tenn., 8 Nov. 1942. Hesler 13094.

Pileus 1-4 cm broad, convex, expanding broadly convex or nearly plane, at first whitish, becoming "ochraceous-buff" to "old-gold" or "olive-ochre," margin paler, appressed-fibrillose, fibrils brown, viscid, margin even. Context thin, thick on the disc, white; odor and taste mild.

Lamellae adnexed or subdecurrent, at first pale yellow, finally "clay-color" or darker, close, medium broad, edges even.

Stipe 2-4 cm long, 2.5-4 (8) mm thick, at times compressed, white above, dingy below, fibrillose, fibrils sometimes forming minute scales downward, dry, solid, equal. Veil arachnoid, white, leaving only a slight fugaceous ring.

Spore deposit dark yellow-brown ("Dresden-brown" to "snuff-brown") spores 5.5-7 (7.5) x 3.5-4 µ; ovate to elliptic in face view, obscurely inequilateral to elliptic in profile; wall about 0.2 µ thick, pale ochraceous tawny in KOH, in Melzer's about the same color, apex obscurely truncate in many.

Basidia 20-24 (27) x 5-6 µ, 4-spored, clavate, hyaline to yellowish in KOH, yellowish in Melzer's reagent. Pleurocystidia scattered to rare; 1) chrysocystidia 22-30 x 5-8 µ, fusoid, fusoid-ventricose to more or less fusoid or clavate-mucronate, with a highly refractive body of amorphous material in the lower part as revived in KOH, walls smooth thin and hyaline; 2) vesiculose-pedicellate cells 23-32 x 8-12 µ, content rich ochraceous in KOH and filling the cells, pedicel narrow. Cheilocystidia 22-33 (56) x 4-5 (8) µ, subcylindric, subclavate, or fusoid-ventricose to tibiiform, smooth, thin-walled, hyaline to yellowish in KOH. Caulocystidia (23) 36-54 x 5-14 (20) µ, clavate to irregular, fusoid-ventricose, vesiculose, clavate-mucronate, etc., but none seen with a refractive amorphous body, thin-walled.

Gill trama of floccose hyaline to yellowish hyphae red-brown in Melzer's reagent, thin-walled, cells short to elongated and smooth; subhymenium a gelatinous, thin layer of narrow (2-3.5) µ hyaline, smooth hyphae subparallel in arrangement. Pileus cutis a gelatinous pellicle of appressed hyphae 2.5-3.5 µ wide, ochraceous in KOH, smooth or nearly so; hypodermial zone not differentiated. Context hyphae smooth, thin-walled becoming slightly thick-walled, cells becoming inflated, inamyloid. Clamp connections present.

Habit, Habitat, and Distribution: On soil, sometimes near sawdust and chips, Gatlinburg, Tenn. Nov. 8, 1942.

Observations: The chrysocystidia are imbedded in the hymenium and are best spotted in revived mounts by the refractive inclusion. In fresh material they are very difficult to spot. The vesiculose bodies are rare in the type but easily located because of their large diameter and their color. The caulocystidia are remarkable for the variation in shape (fig. 116). It appears to be related to P. caespitosa and P. lutescens.

Material Examined: TENNESSEE: Hesler 9641, 13094 (type), Gatlinburg, November 8, 1942.