The North American Species of Pholiota

185. Pholiota avellaneifolia sp. nov.

Illustrations: Text figs. 415; 416-417; pl. 83.

Pileus 4-7 cm latus, convexus, viscidus, badius, luteo-sqamulosus. Lamellae avellaneae adnatae vel decurrentes, confertissimae, angustae. Stipe 4-8 cm longus, 10-20 mm crassus, aequalis, solidus, deorsum demum fulvus et badio-squamulosus, sursum Iuteus. Velum luteum. Sporae 6-7 x 3-3.5 µ. Pleurocystidia 48-75 x 9-20 µ obese fusoide ventricosa. Cheilocystidia 26-48 x 7-15 µ, obese ventricosa, intus cinnamomus et reticulata. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope. McCall, Idaho, 5 Aug. 1958. Smith 59589.

Pileus 4-7 cm broad (immature), convex with an incurved margin, becoming broadly convex to nearly plane, viscid, bay-brown with yellowish patches of veil fibrils. Context thick, firm, whitish; slowly becoming pinkish buff when cut, odor and taste mild.

Lamellae avellaneous young, more rusty in age, adnate to short-decurrent, close or crowded, narrow, edges even.

Stipe 4-8 cm long (immature), 10-20 mm thick, equal, solid, cortex yellowish in apex, pallid elsewhere, slowly pinkish-buff where cut, and eventually dark brown at least below, surface with pale bay squamules over basal portion, yellowish silky up to the zone left by the copious veil, pallid silky above zone. Veil very thick, fibrillose, yellowish.

Spores 6-7 x 3-3.5 µ, oblong to elliptic in face view, rarely ovate or obscurely angular, in profile mostly somewhat bean-shaped, wall rather thin for the genus, pore at apex extremely minute, in KOH pale tawny, in Melzer's reagent about the same.

Basidia 18-24 x 4-5 µ, 4-spored, narrowly clavate, yellowish to hyaline in KOH and Melzer's sol. Pleurocystidia 48-75 x 9-20 µ, broadly fusoid-ventricose to pedicellate-subclavate, pedicel rather narrow (3-5 µ), thin-walled, often with debris adhering over apex, walls thin. Cheilocystidia 26-48 x 7-15 µ, broadly ventricose, content cinnamon brown and reticulate as revived in KOH. Caulocystidia none.

Gill trama of parallel hyphae ochraceous to rusty in thick sections (in KOH) narrow (but all relatively immature), smooth; subhymenium gelatinous. Pileus cutis a very thick gelatinous pellicle of narrow (2-3 µ) hyphae with walls slightly thickened and also some ornamented inconspicuously; hypodermium of bright rusty brown floccose hyphae 3-8 µ diam. and with tawny incrustations. Context hyphae with inflated cells, walls thin, smooth and yellowish in KOH or Melzer's sol. hyaline when single hyphae are isolated). Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: On soil under spruce. McCall, Idaho. 5 Aug. 1958. Smith 59589, type.

Observations: This species is distinguished by the heavy yellow veil and an outer layer which leaves brown squamules over the lower part of the stipe. The avellaneous gills were conspicuous in the young basidiocarps but became olivaceous in drying. The species is closely related to P. sublubrica. However the pleurocystidia of that species do not have the brown content revived in KOH as noted for P. avellaneifolia, and for the latter they more closely resemble those of P. polychroa in shape than those of P. sublubrica. The spores of the latter are paler in Melzer's reagent than in KOH, whereas they are about the same in P. avellaneifolia.