Borov., Rockefeller & P.G.Werner (2012)
Psilocybe allenii is a species of agaric fungus in the family Strophariaceae. Described as new to science in 2012, it is named after John W. Allen, who provided the type collection. It is found in the western United States from Los Angeles, California to Seattle, Washington, most commonly within 10 miles (16 km) of the Pacific coast. The fruit bodies (mushrooms) grow on rotting wood, especially wood chips used in garden landscaping. The caps of the mushrooms are brown to buff, broadly convex to flattened and have a diameter up to 9 cm (3.5 in), while the white stems are up to 9 cm (3.5 in) long and 0.7 cm (0.3 in) thick. As a bluing species in the genus Psilocybe, P. allenii contains the psychoactive compounds psilocin and psilocybin, and it is consumed recreationally for its hallucinogenic properties. It is closely related to Psilocybe cyanescens, from which it differs macroscopically by the lack of a wavy cap margin.
Psilocybe allenii was described as new to science in 2012 by Jan Borovička, Alan Rockefeller, and Peter G. Werner. Borovička received material collected from Seattle, Washington, which he noted was microscopically similar to Psilocybe cyanescens, but lacked the wavy cap margins characteristic of that species. In previous publications, Borovička had noted that both macro- and microscopic characters of certain Psilocybe species were highly variable, which could also account for the differences observed in the Seattle material. However, DNA sequencing revealed a 5-base pair change in the internal transcribed spacer regions (a segment of RNA often used in molecular phylogenetics to identify or distinguish fungal species) between P. cyanescens and the Seattle collections. This difference, in addition to the readily observable macroscopic differences, was deemed sufficient to warrant describing the taxon as a new species. The specific epithet allenii honors John W. Allen, who collected the original material and provided the impetus for the study. Allen collected the type material from the University of Washington Campus in November of 2009.
For several years before its official description, the taxon was known in the San Francisco Bay Area, and suspected of being an undescribed species. The authors suggest that a color photograph of "P. cyanescens" in David Arora's popular 1986 guidebook Mushrooms Demystified may actually depict P. allenii. Mycologist Paul Stamets suggested in 2005 that it "probably is new, or least a newly imported species". It is commonly called "Psilocybe cyanofriscosa" in the online mycological community, but this name is grammatically incorrect Latin and has never been validly published in scientific literature.
Fruit bodies of P. allenii are variable in size, depending on the substrate in which they grow. The caps are 1.5–9 cm (0.6–3.5 in) in diameter, and range from broadly convex to flattened, sometimes with a slight depression in the center. The cap margin is either straight and slightly curved inward, rarely slightly wavy, and sometimes has radial grooves in moist specimens. The surface is smooth, sticky when moist, with a gelatinous cap cuticle that can be peeled. Caps are hygrophanous, and so will change color depending on how moist they are. They are pale orange brown to caramel brown when moist, but dry to yellowish-buff. Gills have an adnate to sinuate attachment to the stem, and are initially cream to pale gray brown, but become dark purple as the spores mature. The cylindrical, hollow stem typically measures 4–7 cm (1.6–2.8 in) long by 0.2–0.7 cm (0.1–0.3 in) thick, with the base slightly thicker. The top of the stem is pruinose (covered with white powdery granules), while the base is connected to thick white rhizomorphs. The stem surface is smooth to silky fibrillose (as if made of silky, slender fibers), and its color initially white before yellowing slightly in age. Mycelium at the base of the stem is white or stained blue. All parts of the fruit body stain blue if bruised or handled. Young specimens have a white partial veil that later disappears, or remains as a zone on the stem that can be colored purplish brown by spores. The odor and taste of the mushroom is farinaceous—similar to freshly ground flour.
Spore prints are dark brown, sometimes with violet shades. Spores are thick-walled with an apical pore, and elongated ellipsoid to equilateral in face view, and somewhat inequilateral in side view, typically measuring 12.0–12.6–13.1 by 6.8–7.1–7.4 μm. The basidia (spore-bearing cells) are cylindrical, four-spored with sterigmata up to 5.5 μm long, and have dimensions of 27–37 by 9–11 μm. Clamp connections are present in hyphae. Cheilocystidia (cystidia on the gill edge) are abundant. They are hyaline (translucent), thin-walled, and variably shaped, and range from narrow clubs to narrow flasks with a neck no longer than 8 μm; their dimensions are typically 20–30 by 6–8 μm. The pleurocystidia (found on the gill face) are common; they are broadly club-shaped but taper to a point (sometimes with a rounded tip at the end), and measure 25–35 by 9–14 μm. Caulocystidia (found on the stem) are also present, with variable shapes similar to the cheilo- and pleurocystidia.
The mushrooms are consumed for their psychoactive properties, and have a potency roughly similar to P. cyanescens. According to Borovička and colleagues, they are "commonly sought out by some mushroom hunters".
Several Psilocybe species have an appearance roughly similar to P. allenii, but these can usually be distinguished by differences in morphology or distribution. The European species P. serbica var. moravica has a similar cap and stem, but is generally more slender than P. allenii. The closely related P. cyanescens is indistinguishable by microscopic characteristics, but features a wavy cap in maturity, a longer fruiting season (from late September through April), and lacks a ring zone on the stem often seen in P. allenii. P. azurescens has a broader cap, an umbo that may be broad or acute, a longer stem up to 20 cm (7.9 in), and a growing season similar to that of P. cyanescens. The authors also note that the Australian P. subaeruginosa is similar (including three taxa that have since been synonymized: P. australiana, P. eucalypta, and P. tasmaniana) but suggest that further research is required to better understand the delimitation of this species complex.
Habitat and distribution
Psilocybe allenii is found in the western United States, with a range extending from Seattle, Washington south to Los Angeles, California. It is most common in areas up to 10 miles (16 km) from the Pacific coast, although it has been collected 100 miles (160 km) inland. Fruit bodies grow scattered, in groups, or (more rarely) in clusters, on woody debris, such as wood chips often used in landscaping. Fruiting occurs in cold weather, generally from late September to January. The species can be readily cultivated on agar, grain spawn, and cellulosic material such as wood chips or sawdust.
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- Borovička J, Rockefeller A, Werner PG. (2012). "Psilocybe allenii – a new bluing species from the west coast, USA" (PDF). Czech Mycology 64 (2): 181–95.
- Borovička J. (2008). "The wood-rotting bluing Psilocybe species in Central Europe – an identification key" (PDF). Czech Mycology 60 (2): 173–92.
- Borovička J, Noordeloos ME, Gryndler M, Oborník M. (2011). "Molecular phylogeny of Psilocybe cyanescens complex in Europe, with reference to the position of the secotioid Weraroa novae-zelandiae" (PDF). Mycological Progress 10 (2): 149–55. doi:10.1007/s11557-010-0684-3.
- Stamets P. (2005). Mycelium Running: How Mushrooms Can Help Save the World. Berkeley, California: Random House Digital. p. 286. ISBN 978-1-58008-579-3.