The North American Species of Pholiota

170. Pholiota stratosa sp. nov.

Illustrations: Text figs. 367-370; pl. 76.

Pileus 2-4 cm latus, demum campanulatus vel late convexus, viscidus, subvirgatus, vinaceo-cinnamomeus. Contextus pallide subluteus, crassus, firmus; sapor mitis; odor fragrans. Lamellae confertae, latae, brunneolae demum ligno-brunneae. Stipes 3-6 cm longus, 4-10 mm crassus, solidus, fibrillosus. Vellum luteum. Sporae 7-10 x 4.5-5.5 µ. Pleurocystidia 50-78 x 7-12 (15) µ, tenuitunicatae. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope Whitmore Lake, Mich. 14 Oct. 1961, Smith 64684.

Pileus 2-4 cm broad, obtuse with an incurved sterile margin, becoming campanulate to broadly convex, viscid but soon dry, covered by a vinaceous-tawny (almost "Mikado brown") epicutis which breaks up into obscure patches and streaks, margin paler in some (pinkish-buff to pale pinkish-buff) and typically fringed with fibrils from an almost cortinate veil. Context pale buff, thick, firm; odor faintly fragrant, taste mild; FeSO4 olive, KOH orange brown.

Lamellae adnexed, pallid brownish becoming near wood-brown, close, moderately broad, edges even.

Stipe 3-6 cm long, 4-10 mm thick, solid, pallid within, covered over all to near apex with fibrils paler than those of cap and leaving an apical zone when veil breaks. Veil yellow.

Spores 7-10 x 4.5-5.5 µ, smooth, ochraceous tawny in KOH, apical pore small but distinct, in face view elliptic varying more rarely to ovate and a very few somewhat angular, in profile elliptic to obscurely inequilateral; color pale reddish tawny in Melzer's reagent or a very few spores dark bay; wall as revived in KOH about 0.5 µ thick.

Basidia 4-spored, 25-32 (37) x 6-8 (10) µ, both 2-, and 4-spored, clavate, hyaline in KOH, yellowish hyaline in Melzer's reagent. Pleurocystidia 50-78 x 7-12 (15) µ, basically fusoid-ventricose with flexuous walls in neck in many, also tending to branch either in ventricose part or above, pedicel narrow and thin-walled, neck often incrusted with amorphous material, with homogeneous content in either KOH or Melzer's reagent, thin-walled. Cheilocystidia similar to pleurocystidia but often smaller. Caulocystidia none.

Gill trama of hyaline subparallel hyphae 3-6 µ broad, the walls thin, hyaline in KOH, smooth, non-gelatinous, cells short to elongated and inflating only in age; subhymenium a broad zone of narrow gelatinous interwoven hyaline hyphae, smooth, and thin-walled, the gelatinization extending to base of basidia near gill edge. Pileus cutis a poorly formed narrow zone of subgelatinous hyphae incrusted with ochraceous-brown pigment, hyphae 3-5 µ broad; beneath this a thick hypodermium of nongelatinous hyphae 5-15 µ broad with rusty brown bands and spirals of pigment. Context hyphae yellow to hyaline in KOH, walls thin and smooth, cells inflated to 60 µ at times, mostly 10-15 µ diam., some bright ochraceous oleiferous hyphae present. Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: On decayed hardwood (Acer rubrum), Mud Lake Bog, Washtenaw County, Michigan. Oct. 14, 1961, Smith 64684, type.

Observations: This species resembles P. graveolens but has slightly larger spores, only a faint pleasant odor, and a very poorly developed gelatinous pellicle. The pleurocystidia, in addition, are much more versiform in P. stratosa, and the structure of the pileus context also appears to be different.