The North American Species of Pholiota

203. Pholiota acutoconica sp. nov.

Illustrations: Text figs. 463-465.

Pileus 3-6 cm latus, conicus demum conico-campanulatus, viscidus, virgatus, ad marginem appendiculatus, laete vel sordide ochraceus. Lamellae late adnatae vel subdecurrentes, confertae, latae (5-6 mm), pallide citrino-luteae deorsum sordide argillaceae. Stipes 5-7 cm longus, 5-8 mm crassus, aequalis, citrino-luteus, deorsum subfulvus, luteo-fibrillosus. Sporae 6-8 x 4-4.5 µ, leves. Pleurocystidia 46-70 x 8-16 µ, fusoide ventricosa, tenuitunicata. Specimen typicum legit prope Rhododendron, Oregon, 2 Oct. 1944. Smith 19315, in Univ. of Mich. conservatum est.

Pileus 3-6 cm broad, conic with an incurved margin, expanding to conic-campanulate, or conic umbonate, the umbo acute, surface viscid, fibrillose-streaked (virgate) beneath the viscid pellicle, margin with thin patches of the fibrillose remains of the veil, "tawny-olive" on disc "honey-yellow," on margin or at extreme edge "Reed's yellow." Context pliant, thin except on the disc, near "honey-yellow" (more dingy than gills); odor none, taste mild.

Lamellae broadly adnate becoming subdecurrent, moderately close, 3 tiers of lamellulae, moderately broad (5-6 mm near stipe) tapered to cap margin, "Reed's yellow" young, finally dingy clay-color, edges even.

Stipe 5-7 cm long, 5-8 mm thick, equal, hollow, when young "Reed's yellow" over all and fibrillose from "Reed's yellow" veil remnants, apex silky and "citron-yellow," gradually becoming "sepia" inside and out from the base upward, cortex yellow, pith usually worm-eaten and tawny in color. Veil yellow, arachnoid.

Spores 6.5-8 x 4-4.5 (9 x 5) µ, smooth, ochraceous tawny revived in KOH, in Melzer's reagent pale cinnamon with a minute apical pore, in face view elliptic varying to ovate, in profile subelliptic to obscurely inequilateral; wall less than 0.3 µ thick and becoming appreciably thicker in KOH.

Basidia 18-25 x 6-7 (8) µ, 4-spored, clavate, yellowish in KOH and Melzer's reagent. Pleurocystidia abundant, 46-70 x 8-16 µ, broadly to narrowly fusoid-ventricose varying to subfusoid, neck usually greatly elongated and apex obtuse, walls thin and many cells remaining collapsed, smooth, content homogeneous and yellowish to hyaline in either KOH or Melzer's reagent. Cheilocystidia similar to pleurocystidia but usually shorter and more frequently varying to subfusoid to nearly clavate and 30-45 x 8-12 µ, content homogeneous in KOH and Melzer's sol., walls thin and smooth. Caulocystidia present as clavate end-cells 9-14 µ broad.

Gill trama of parallel to somewhat interwoven hyaline (in KOH) to yellowish thin-walled, smooth non-gelatinous hyphae 3-8 µ diam. with short (near pileus) to elongate hyphal cells; cells becoming somewhat inflated in age; subhymenium of gelatinous or subgelatinous narrow (3-5 µ) hyaline smooth-walled hyphae in a zone intergrading with the central strand. Pileus cutis a gelatinous layer of hyphae 2-5 µ diam., the walls collapsing and disintegrating, in the process becoming crinkled and often appearing ornamented with incrustations; hypodermium a layer of interwoven hyphae dark orange-brown in KOH and of hyphae 5-12 µ diam. with heavily incrusted walls. Context hyphae interwoven, walls yellow in KOH and smooth, cells inflated to 15+ µ, inamyloid (yellow in Melzer's reagent). Clamp connections present.

Habit, Habitat, and Distribution: Caespitose to gregarious around conifer wood, Rhododendron, Oregon. Oct. 1, 1944. Smith 19315, type.

Observations: This species bears a strong resemblance to species of subg. Flammula but is at once distinguished by its large pleurocystidia. It is a brighter yellow than P. spumosa and the color is more persistent, in fact it is an outstanding field character along with the sharply conic pileus. There is a difference in spore color on spores revived in KOH also. In P. acutoconica they are near ochraceous tawny.