Macroscopic feat.:

• Cap/Pileus: 5-15 (-20) mm diam, campanulate to subpapillate, glabrous, smooth but striate towards the margin. subviscid, hygrophanous. dark buff to coffee brown, bluing.
• Gills/Lamellae: Adnexed, dark violaceous brown, with concolorous edges.
• Stem/Stipe: 50 (-60) x 0.5-1 mm, uniform, smooth. brownish to dark brownish red, hollow, bluing. Veil ephemera.
• Context: Brownish, bluing.

Microscopic feat.:

• Basidio/Spores: 5-5.5 x 4-5 x 3-4 µm, subrhomboid or subglobose in face-view, subellipsoid and slightly inaequilateral in side-view. thick-walled, wall up to 1 µm thick, pale yellowish brown, with a distinct plane and apical pore, and with a short basal appendage.
• Basidia: 20-32 x 5-7 µm, 4-spored, subcylindric to clavate, hyaline.
• Pleurocistidia: 13.5 x 5-7 µm, more or less abundant, hyaline, sublageniform with a long tapering apex.
• Cheilocystidia: 16-24 x 5-7 µm, hyaline, sublageniform, with two or three regular or irregular long necks.
• Subhymenium: Subcellular, poorly differentiated, with hyaline, subcylindrical or subglobose, thin-walled elements 2.5-5.5 µm diam.
• Trama: Hymenophoral trama regular, with hyaline to yellowish hyphae 4-9 µm, with inflated hyphae up to 28 µm diam, thin- to thick-walled (wall up to 2 µm thick), irregularly incrusted with yellowish pigment.
• Epicutis: An irregular, thin. gelatinized layer of pale yellowish hyphae, 1.5-3 µm diam.
• Hypodermium: With cylindric to subglobose elements 2.5-9.5 µm, diam. hyaline to yellowish, thin-walled and with incrusted yellowish pigment. Context with cylindric to subglobose elements, 4-10 µm, diam, hyaline to yellowish, thin- to thick-walled, with irregular yellowish incrustations. Clamp-connections present.

Habitat: Gregarious or solitary on muddy clay brownish soil or humus in a coffee plantation, along a trail, in a mesophytic forest. Known only from Puerto Rico.

Studied material: PUERTO RICO, Municipio Villalba, Toro Negro State Forest, trail to Torre 3 (18°10'N, 66°30'W), 820-1015 m alt., Oct. 1994, Nieves-Rivera, Santos-Flores & Betancourt s.n. (holotype MAPR; isotype XAL).

Discussion: This species belongs to Sect. Cordisporae Guzmán by virtue of their smaller rhomboid spores, bluing feature and subtropical habitat. It is close to Psilocybe subtropicalis Guzmán, from Mexico and Guatemala, by the branched cheilocystidia, but that species has spores (5.5-) 6.5-7 (-8) µm long and collybioid habit (Guzmán, 1995). Psilocybe plutonia differs with pleurocystidia broadly ventricose, ventricose-mucronate or obpyriform, 17-26 (-30) x 9-12 µm (Guzmán, 1983, 1995).

source - www.mycotaxon.com [63: 379-380]

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