The North American Species of Pholiota

37. Pholiota tennesseensis sp. nov.

Illustrations: Text figs. 125-127; pl. 15.

Pileus caespitosus, 1.5-3.5 (7) cm latus, eburneo-albus demum eburneo-flavus vel "light-buff" tinctus colore obscuro-olivaceo, disco "chamois" demum "warm-buff," denique obscure flavo-albus, fibrillosus, squamosus vetus. Caro alba; odore et gustu mitis. Lamellae adnatae vel adnatodecurrentes, albae deinde flavidae, denique "honey-yellow" demum "claycolor," confertae, medio-latae. Stipes 2-3.5 (6) cm longus, 5-8 (10) mm crassus, albidus vel tinctus colore flavido, obscure flavido-brunneus, fibrillosus. Velum album, arachnoideum, fugax. Sporae (4.5) 5-7 (7.5) µ, ellipsoideae vel subovoideae, leves, truncatae. Pleurocystidia desunt; cheilocystidia 22-48 x 4-9 µ, ventricosa demum cylindrica. Cuticula gelatinosa. Caulocystidia versiformia. Specimen typicum in Herb. Univ. Tenn.; legit in Knoxville, Tennessee, November 18, 1945, Hesler 18848.

Pileus caespitose, 1.5-3.5 (7) cm broad, viscid, ivory white to "ivory-yellow," or "light-buff" with an obscure olive tint, disc "chamois" to "warm-buff," finally dingy yellowish-white over all, with scattered brownish fibrils, usually becoming scaly in age, margin even, at first appendiculate. Context white, at maturity yellowish under the cuticle; odor and taste not distinctive

Lamellae adnate, or adnate-decurrent, at times more or less adnexed, at first white or pallid, soon yellowish, finally dull yellow to yellow-brown ("honey-yellow" to "buckthorn-brown" or "clay-color), close, moderately broad, edges even or nearly so.

Stipe 2-3.5 (6) cm long, 5-8 (10) mm thick, whitish with a yellowish tint, apex white-silky, elsewhere with dingy yellowish brown fibrils or scales, equal or tapering downward, stuffed then hollow. Veil white, arachnoid, leaving a superior annular fibrillose zone, fugaceous.

Spore deposit dark yellow-brown ("Prout's brown" to "snuff-brown"); spores (4.5) 5-7 (7.5) x 3.3-4 µ, elliptic to ovate in face view, obscurely inequilateral in profile, wall only slightly thickened (not enough to estimate thickness), tawny to near amber brown in KOH, merely pale reddish tawny in Melzer's reagent, smooth, apex obscurely truncate.

Basidia 24-30 x 5-7.5 µ, 4-spored, clavate, hyaline in KOH, yellowish in Melzer's sol. Pleurocystidia scattered as chrysocystidia, 31-46 x 8-12 µ, clavate-mucronate to obclavate to more or less fusoid-ventricose, as revived in KOH with the typical hyaline amorphous mass of material in the enlarged part or in the broad pedicel, thin-walled, smooth, yellowish in Melzer’s. Pseudocystidia filamentous to clavate 25-34 x 5-10 µ, bright yellow in KOH, scattered in hymenium. Cheilocystidia 18-26 (48) x 4-9 µ, fusoid-ventricose to utriform, apex obtuse to rounded, often with yellowish content in KOH but content homogeneous. Caulocystidia mostly clavate as projecting terminal cells of hyphae, 33-60 x 5-8 µ, thin-walled, hyaline to yellowish in KOH and Melzer's sol.

Gill trama of subparallel hyphae with cells elongate, tubular or nearly so (until old age), non-gelatinous, (3) 4-8 (12) µ wide, thin-walled, hyaline to yellow in KOH and Melzer's reagent; golden yellow oleiferous hyphae numerous (as revived in KOH); subhymenium of interwove filamentous hyphae 2-3.5 µ diam., hyaline and subgelatinous as revived in KOH. Pileus cutis a gelatinous pellicle of interwoven hyphae hyaline to bright ochraceous in KOH, tubular, 3-5 µ diam.; golden lactiferous (or oleiferous?) hyphae also in the layer; hypodermial zone not structurally distinct from context (possibly containing more oleiferous hyphae). Context hyphae (3) 6-12 (22) µ wide, cells becoming greatly inflated, golden oleiferous hyphae also present. Clamp connections present. All hyphae inamyloid but occasional small masses of amyloid debris noted.

Habit, Habitat, and Distribution: Clustered to gregarious on soil in lawns, Tennessee, November-December, Hesler 18848 type, and 17246, 18848, 18871, and 25006.

Observations: This is a most interesting species from the standpoint of the yellow-brown spore deposit, tendency for the subhymenium to gelatinize, the obscurely truncate spores and presence of chrysocystidia. It is excluded from Naematoloma by the color of the spore deposit. The bright yellow pseudocystidia in the hymenium are fairly rare in the material examined to date but we feel they are significant as a species character. We would not emphasize the amyloid debris at this time as a taxonomic character, though it must be admitted that this sort of material is very rare in the genus as we have studied it to date. In the herbarium the bright yellow pseudocystidia distinguish this species from P. caespitosa. In the field P. caespitosa is basically whitish and has a yellow veil. P. tennesseensis has yellowish brown scales on the stipe, and the pileus when young is pale yellow or tinged with olive.