Psilocybe ovoideocystidiata A spring-fruiting psilocybin mushroom expanding across Pacific Northwest cities
Psilocybe ovoideocystidiata is a small, blue-bruising mushroom that grows on wood chips and fruits mainly in spring. It was first collected in Montgomery County, Pennsylvania, in 2003 and formally described in 2007. In the East it also grows on wood debris in deciduous forest; on the Pacific coast it has been found only on wood chips, not in the wild (Borovička), and has been recorded in Washington, Oregon and California.
This species contains psilocybin and psilocin. It fruits primarily in spring, which is unusual among PNW Psilocybe, and in the PNW grows on landscaping wood chips and mulch in urban and suburban settings.
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Identification
Identifying any Psilocybe to genus requires a combination of features — no single trait is sufficient. Start with a spore print, look for blue bruising, and ideally collect specimens at different stages of maturity.
| Feature | Description |
|---|---|
| Cap | 1.5–2.5 cm (range 1–4.5 cm). Convex to slightly umbonate. Orangish brown to yellowish brown when moist, fading paler, sometimes to whitish, as it dries (hygrophanous). Slippery to slightly sticky when wet, with a translucent-striate margin. Bruises blue. |
| Gills | Narrowly attached (subadnate). Pale brownish when young, darkening to dark violet-brown as spores mature. |
| Stem | 2.5–6 cm tall (range 1.5–9 cm), 2–5 mm thick, hollow, sometimes slightly bulbous. Whitish, bruising blue, with pale ocher to violet tones; smooth above, floccose-scaly below, with white mycelium at the base. A white, membranous but short-lived ring, described as distinct and cortina-like by Siegel. |
| Spore Print | Dark purple-brown to purple-black. This is the most reliable first step — many LBM lookalikes have brown or rusty-brown spore prints instead. |
| Bruising | Blue to blue-green where flesh is damaged — stems, cap edges, and damaged gills. Caused by oxidation of psilocin. Not always immediate; may take minutes to develop. |
| Odor | Farinaceous (flour-like). |
| Habitat | Wood chips and mulch in urban and suburban settings. On the Pacific coast it has not been found in the wild (Borovička). |
Spring timing is the strongest field clue in the PNW
A small wood-chip mushroom with dark purple-brown spores and blue bruising, fruiting in April or May in an urban PNW setting, is most likely P. ovoideocystidiata. The other wood-chip Psilocybe here (P. cyanescens, P. allenii, P. stuntzii, P. baeocystis) fruit in fall and early winter, although P. cyanescens occasionally fruits in spring. Timing supports an identification but never replaces the spore print.
Photo Gallery
Specimens vary considerably in appearance depending on age, moisture, and growing conditions. This gallery shows the range of variation you may encounter.
Habitat & Distribution
In the PNW, P. ovoideocystidiata is found on landscaping wood chips and mulch: garden beds, borders, walkways and park paths.
It was described from the eastern United States, where it also grows on wood debris in deciduous forest. On the Pacific coast it has been found only on wood chips and not in the wild (Borovička), which is consistent with it having been introduced here.
Blue-bruising Psilocybe found in fall are more likely P. cyanescens, P. allenii or P. stuntzii.
Track Spring Conditions in Your Area
Soil temperature and 14-day precipitation layers on Forayz can help you anticipate fruiting windows for spring species across the Pacific Northwest.
Season & Timing
In Oregon and Washington, most fruiting is in April and May, at about the same level, with fewer in March and June. A smaller flush appears from October to December. Community observations from Oregon and Washington show this bimodal pattern:
Based on community observations from Oregon and Washington
The spring peak is the clearest difference from the other PNW Psilocybe: P. cyanescens, P. allenii, P. stuntzii and P. baeocystis all fruit in fall or early winter.
Lookalikes & Safety
The biggest risk with any small brown mushroom (LBM) is misidentification. Several toxic species, two of them deadly, share the same wood-chip habitat:
- Galerina marginata (Deadly Galerina): Contains amatoxins, the same toxins as the death cap, and often grows alongside Psilocybe in wood chips, where it tends to cluster. Mostly late summer and fall, occasionally in spring. Key differences: a rusty-brown spore print (not purple-black), no blue bruising, and a stem that is orangish and darkens from the base up. Its ring is often faint or collapsed, and P. ovoideocystidiata also has a ring, so don’t use the ring to separate them.
- Pholiotina rugosa: Also deadly, with amatoxins. Grows in wood chips and compost-rich soil, with its main flushes in spring and fall — the same place and season as P. ovoideocystidiata. Small, with a reddish-brown hygrophanous cap that fades to ocher-buff, a conspicuous white disc-like ring, and a dark ocher-brown spore print. No blue bruising.
- Psathyrella species: Common on wood and woody debris and easily confused at a glance. Spore prints are dark brown and in some species dark purplish brown, so the print alone doesn’t rule them out. No blue bruising.
- Hypholoma fasciculare (sulphur tuft): Grows in clusters on wood. Its spore print is dark purple-brown to purplish black, like Psilocybe. Told apart by its yellow to greenish-yellow gills and stem, bitter taste, and lack of blue bruising. Toxic, causing severe gastrointestinal illness; deaths have been reported in Europe and Asia (Arora).
- Psilocybe cyanescens / P. allenii: Not deadly, but distinct species. Both fruit on wood chips in fall and early winter and are generally larger. P. cyanescens has a caramel cap with a strongly wavy edge; P. allenii is rarely wavy and stouter.
Spore print first, always
A dark purple-brown spore print combined with blue bruising is the minimum for considering a Psilocybe identification. Rusty-brown spores point to Galerina and dark ocher-brown spores to Pholiotina, both of which can be fatal. Never rely on cap color, habitat or season alone: both deadly species grow in the same wood chips, and Pholiotina rugosa flushes in spring.
Legal Status
Psilocybin-containing mushrooms are classified as Schedule I controlled substances under federal law. State laws vary — Oregon has established a regulated psilocybin services program (Measure 109, effective 2023), and several other states and cities have decriminalization measures in place. This page is for identification and educational purposes only.
Sources: Mushrooms of Cascadia (Siegel & Schwarz, 2024); MycoMatch (© Ian Gibson), a compilation of published descriptions through which most other field-guide authors named here are quoted.