The North American Species of Pholiota

77. Pholiota parvula sp. nov.

Illustrations: Text figs. 98-101; pl. 7c.

Pileus 1-2 cm latus, convexus demum planus, viscidus, pallide fulvus. Contextus albus. Lamellae adnato-sinuatae, confertae, pallidae, latae. Stipes 3-6 cm longus, 2.5-3.5 mm crassus, deorsum attenuatus, sparse fibrillosus vel squamulosus, glabrescens, sursum pallide luteus, deorsum tarde sordide brunneus. Sporae 6-7.5 x 3.5-4.5 µ, leves, subtruncatae. Pleurochrysocystidia 22-30 x 6-10 µ. Cheilocystidia 28-40 x 3-7 µ, subcylindrica vel fusoide ventricosa. Specimen typicum in Herb. Univ. Mich. conservatum est., legit prope Wilderness State Park, Mich. 24 Sept. 1953. Smith 43234.

Pileus 1-2 cm broad, convex, becoming plane, viscid, ochraceous tawny to near tawny on disc, margin pale cinnamon-buff to cinnamon-buff, in age the colors paler (near clay color), with veil remnants along the margin. Context white; odor and taste none.

Lamellae adnexed, close, broad, pallid, then pale cinnamon-brown, edges even.

Stipe 3-6 cm long, 2.5-3.5 mm thick at apex, narrowed downward, yellowish, faintly fibrillose to squamulose from the veil fibrils but these soon evanescent, in age becoming dark (more or less bister) from the base upward, apex naked or nearly so. Veil yellow, arachnoid.

Spores 6-7.5 x 3.5-4.5 µ smooth, apical pore distinct and apex in some slightly truncate, shape in face view elliptic to ovate, in profile slightly bean-shaped to obscurely inequilateral, dull cinnamon in KOH, slightly paler in Melzer's reagent, wall about 0.25 µ thick.

Basidia 20-24 x 5-6 µ, 4-spored, clavate, yellowish in KOH, the same in Melzer's reagent. Pleurocystidia numerous, 22-30 x 6-10 µ, oval, elliptic, clavate or slightly mucronate, with a large refractive inclusion yellow to orange-brown in Melzer's reagent; wall thin, smooth and hyaline. Cheilocystidia 28-40 x 3-7 µ, subcylindric to fusoid-ventricose, often irregular in outline; wall thin, smooth and hyaline, content homogeneous. Caulocystidia in the form of chrysocystidia 28-42 x 5-10 µ, elongate fusoid-ventricose with refractive inclusion varying to clavate ellipsoid etc., or homogeneous and resembling cheilocystidia.

Gill trama of parallel hyaline hyphae with rather short cells, walls thin and smooth, the cells 3-11 µ diam., inflated in age; subhymenium scarcely differentiated (not gelatinous). Pileus cutis a gelatinous layer of widely spaced ochraceous incrusted hyphae in KOH; hypodermium of dark rusty brown coarsely incrusted hyphae 4-10 µ diam. Context hyphae interwoven, with thin smooth yellowish walls (in KOH). Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: Caespitose to gregarious, on hardwood, Michigan, September.

Observations: This species is distinguished by its small size, white flesh, pallid gills, yellow veil, yellowish stipe, medium sized spores, and short, inconspicuous pleurocystidia in the form of chrysocystidia. The caulocystidia are in tufts.

Material Examined: MICHIGAN: Smith 43158 (type), 43234, 50514, 50578, 50726, 51245.