The North American Species of Pholiota

61. Pholiota sipei sp. nov.

Illustrations: Text figs. 75-77.

Pileus 2-4.5 cm latus, "light-drab," umbone "cinnamon-drab," viscidus, margine striatulatus. Lamellae sinuosae, concolores, confertae, mediolatae. Stipes 5-7 cm longus, 4-7 mm crassus, flexuosus, basi parvum bulbosus, supra planus, infra albus cum flavidis squamis. Velum album membraneum manifestum. Sporae 9-12 x 4.5-6 µ, ellipsoideae, truncatae. Pleurlocystidia 41-64 x 10-18 µ, ampullacea, ventricosa vel clavata. Cheilocystidia 25-58 x 7-12 µ, ventricosa, clavata. Pilei trama stratosa, gelatinosa. Cuticula gelatinosa. Caulocystidia desunt. Specimen typicum in Herb. Univ. Mich.; lectum prope Williamette, Oregon, November 16, 1947, Sipe 1059.

Pileus 2-4.5 cm broad, glabrous, very viscid, margin finely striate, margin in some hung with fragments of the veil; color light drab over the marginal area and drab over the umbo (dull gray on disc and paler on margin, as dried marginal area olive grayish and disc dull fulvous).

Lamellae sinuate, close, moderately broad, pallid to avellaneous becoming cinnamon from the spores.

Stipe 5-7 cm long, 4-7 mm thick, flexuous, sometimes bulbous at base, smooth above the ring, white with yellowish floccose scales below the ring. Veil white to yellowish, membranous, leaving a distinct membranous annulus and at times pileus margin decorated with particles.

Spores 9-12 x 4.5-6 µ, elliptic in face view, mostly obscurely inequilateral in profile; smooth, thick-walled (1.5 µ ±), apex distinctly truncate from an obvious apical pore; dull tawny to pale bister in KOH, dull tawny in Melzer's reagent.

Basidia 26-33 x 7-9 µ, 4-spored, clavate, hyaline in KOH and yellowish in Melzer's reagent. Pleurocystidia of two types: 1) chrysocystidia 20-35 x 8-12 µ, clavate to mucronate, thin-walled, hyaline in KOH, with a highly refractive body or globule which in Melzer's reagent merely stains ochraceous; 2) giant leptocystidia 50-75 x 10-20 µ, fusoid-ventricose with rounded to obtuse apices, wall thin and delicate (readily collapsing and difficult to revive), content homogeneous. Cheilocystidia numerous, 26-58 x (7) 10-15 µ and broadly utriform, some giant cells like the hymenial leptocystidia also present. Caulocystidia none found.

Gill trama of hyaline thin-walled hyphae subparallel-interwoven, the cells tubular at first and 3-6 µ diam., inflating to 5-12 µ diam. at least near pileus trama, yellowish in Melzer's reagent; subhymenium narrow and indistinct to slightly gelatinous as revived in KOH. Pileus cutis with a thick gelatinous pellicle of loosely interwoven hyaline hyphae 3-4 µ diam., imbedded in slime, walls smooth and sharply defined as revived in KOH; hypodermium of pale tan non-gelatinous thin-walled hyphae the cells inflated to 12 µ or more, walls smooth but slightly colored. Context hyphae hyaline, 5-10 µ diam., or becoming more inflated, somewhat gelatinous in subhymenial area. All hyphae inamyloid. Clamp connections present.

Habit, Habitat, and Distribution: On soil under fir, near Willamette, Oregon, Nov. 16, 1947, Sipe 1059 type.

Observations: This is a very distinctive species closely related to P. albivelata but with larger spores. The basidiocarps are very similar in basic aspect, but there are major microscopic differences as is readily seen by comparing the descriptions. Sipe's notes clearly indicate the spores as cinnamon, and the gills as becoming cinnamon from the spores, otherwise one would immediately place the species in Stropharia where the combination of chrysocystidia and leptocystidia in the hymenium is by no means unique. The annulus is slightly more flocculose than that of P. albivelata and tends to be yellowish. We cannot state positively that caulocystidia are lacking, though we could find none on the material available for examination. We take pleasure in naming this species for the well known Oregon naturalist Dr. Frank P. Sipe, the collector.