The North American Species of Pholiota

20. Pholiota lactea sp. nov.

Illustrations: Text figs. 28-30.

Pileus 1-2 cm latus, convexus, fibrillosus, siccus, pallide luteus. Lamellae latae, late adnatae, confertae, albidae demum pallide brunneae. Stipes 2-4 cm longus, 1-2.5 mm crassus, sursum pallidus, deorsum subbadius. Sporae 8-10 x 4.5-5 µ. Pleurocystidia desunt. Cheilocystidia 28-36 x 8-12 µ, clavata vel fusoide ventricosa. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope Lower Tahoma Creek, Mt. Rainier Nat'l. Park, Wash. 4 Oct. 1952, Smith 40539.

Pileus 1-2 cm broad, convex, expanding to broadly convex, surface dry and fibrillose, somewhat areolate in age, pale yellow to pallid (near "warm buff") over all or with the disc darker (pale clay-color), margin finally whitish and long remaining appendiculate from veil remnants. Context firm, colored like the surface, odor and taste not distinctive.

Lamellae broad, broadly adnate, close, whitish when young, becoming pale dull brown.

Stipe 2-4 cm long, 1-2.5 mm thick at apex, equal to a small basal bulb, pallid above, dingy red-brown below, at first decorated with veil remnants which terminate in an evanescent annular zone.

Spores 8-10 x 4.5-5 µ, somewhat inequilateral in profile, in face view narrowly ovate to elliptic, smooth with a distinct apical pore; rusty cinnamon in KOH, wall thickened, plage area not differentiated.

Basidia 20-23 x 7-8 µ, 4-spored, hyaline in KOH. Pleurocystidia none. Cheilocystidia abundant (edge heteromorphic), 28-36 x 8-12 µ, clavate to fusoid-ventricose with only slightly narrowed neck and rounded apex, smooth, thin-walled, hyaline in KOH. Caulocystidia abundant near apex of stipe, 28-45 x 6-11 µ, subcylindric to ventricose at base and neck elongated to an obtuse apex; walls flexuous and thin to slightly thickened.

Gill trama subparallel, of inflated thin-walled hyphae, hyaline in KOH; subhymenium not distinctive. Pileus trama floccose-interwoven, the hyphal walls smooth and yellowish in KOH. Pileus cuticle a layer of fulvous (in KOH) walled hyphae with incrusting pigment, with cells considerably enlarged (15-50 µ in diam.) and often elliptic to subglobose. Terminal cells often clavate, yellow-fulvous in KOH. Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: Gregarious on soil, lower Tahoma Creek, Mt. Rainier Nat'l. Park, Washington, Oct. 4, 1952, Smith 40539, Type.

Observations: This species connects to section Inoderma of Galerina, but there is no demarcation of the plage area of the spores as in those species. If P. lactea were to be placed in Galerina it would more properly belong in section Porospora. However, in its spore characters and the characters of the pileus cutis it falls naturally in this section of Pholiota. The discovery of such species as this in our estimation clearly connects Pholiota to the Galerina-Tubaria complex. The basidiocarps of P. lactea are a pale buff as dried, but show the typical darkening reaction of the stipe and pileus cutis when revived in KOH.