The North American Species of Pholiota

191. Pholiota milleri sp. nov.

Illustrations: Text figs. 511-513.

Pileus 2-3.5 cm latus, obtuse conicus, subviscidus, virgatulus, sordide cinnamomeus. Contextus albus. Lamellae brunneolae, anguste confertae; stipes 3-5 cm latus, 4-8 mm crassus, sursum citrino-pallidus, deorsum pallidus vel subsordidus. Sporae 6-8 x 4-4.5 µ. Pleurocystidia 50-70 x 10-15 µ, tenuitunicata. Specimen typicum in Herb. Univ. of Mich. conservatum est; legit prope Priest River Experimental Forest, 6 Juli 1964. O. K. Miller 2382.

Pileus 2-3.5 cm broad, obtuse, expanding to obtusely conic or campanulate, umbonate, surface slightly viscid but soon dry and appearing obscurely fibrillose or streaked, near "Verona-brown" unless darkened from spores. Context white, odor none, taste mild; FeSO4 olive, KOH on cutis no reaction.

Lamellae adnate, dull brown when young, darker than "Verona-brown" when mature, crowded, narrow, edges even.

Stipe 3-5 cm long, 4-8 mm thick, equal or base with a slight rounded bulb, surface above citrine-pallid and with very inconspicuous fibrils or squamules from a rudimentary veil, base not darkening.

Spores 6-8 x 4-4.5 µ smooth, apical pore small but evident; shape in face view oblong to elliptic, in profile elliptic to obscurely inequilateral; in KOH dark rusty, cinnamon, paler but reddish cinnamon in Melzer's reagent; wall about 0.3 µ thick.

Basidia 24-27 x 5-7 µ, 4-spored, short-clavate, ochraceous in KOH and in Melzer's reagent. Pleurocystidia 50-70 x 10-15 µ, fusoid-ventricose, apex obtuse, wall thin, smooth; content homogeneous or with refractive rods and particles near apex, yellow to hyaline, often yellow only in the neck. Cheilocystidia 30-54 x 8-12 µ obtusely fusoid to fusoid-ventricose, obclavate to nearly ellipsoid, smooth, often with refractive particles near or at apex. Caulocystidia 45-70 x 5-14 µ, clavate, subcylindric, fusoid-ventricose or irregular, walls thin but yellow in KOH, content homogeneous.

Gill trama of subparallel floccose hyphae with enlarged cells, the walls thin, smooth, yellowish to hyaline in KOH; subhymenium a narrow gelatinous layer, structure very soon indistinct. Pileus cutis a thick layer of narrow mostly hyaline hyphae collapsing and becoming reticulate, incrusted near hypodermium, 2-3.5 µ diam.; hypodermium of floccose heavily incrusted rusty-brown hyphae in KOH. Context hyphae inflated, smooth thin-walled and yellowish in KOH. Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: On soil, Idaho, July, type. Miller 2382.

Observations: The distinctive characters of this species include its narrow gills which are dull brown at first, and its brown, umbonate pileus. It has some relationship to P. subtestacea, which has a brick-red to pinkish pileus as dried, broad gills which are at first white, and a testaceous veil. The non-darkening stipe base and consistently thin-walled pleurocystidia distinguish it from P. decorata.