Psathyrella and Panaeolus

These are very fragile mushrooms. In fact, one criteria for identification is that the mushroom does not survive the trip to bring it to an identifier. Psathyrellas are related to most inky caps, except they do not have the enzyme to turn to ink and the caps are not strongly striate. Both have dry, hygrophanous caps, usually attached gills that easily come free, black (or very dark) spores and they often have white stems. Only occasionally does the partial veil leave a ring. They are all saprophytic.

There are about 160 species reported from the PNW but they are little studied and only now is DNA beginning to give us a sense of which are distinct species. The best resource we have is Alexander Smith's "The North American Species of Psathyrella". Smith described 414 species. My preliminary study has found type sequences or other reliable sequences of about 91 of our 160 PNW species, with only about 67 species left in the "Little Known Psathyrella" category. For more details, see here.

I admit I have a special penchant for Psathyrella, maybe because they are an underdog mushroom that few people seem to care about, but they have a special gracefulness. Cautious experimentation has shown many species of Psathyrella to be edible and delicious, but you need a lot of them to make any kind of quantity. Do not try this yourself as they are difficult to ID correctly to species and there have been no real studies of their safety.

Panaeolus are very difficult to tell apart from Psathyrella, but they belong in their own family. Their blackish spores mature irregularly, making some black and some paler spores on the gills at the same time, giving them a mottled appearance (more often than you see in Psathyrella). They are more likely to be found in grass or dung than Psathyrella and usually have stiffer stems less likely to be white. There are also several hallucinogenic species.

The mushrooms in the Psathyrella and Paneolus families have a cellular cap cuticle (the top layer of cells are inflated and round) like Agrocybe and the Bolbitiaceae (and the Russulaceae, but their entire fruitbody has round cellular elements). This sometimes gives them a subtle granular look (and often makes them wrinkle and sparkle in the sun), but it also makes them susceptible to breaking in any direction, not just radially from the cap to the centre. Put a little bit of pressure on the cap by bending it and see if you can get it to easily break like in the first picture - that might indicate a cellular cap cuticle, although an old rotting mushroom of any kind is also likely to break easily in any direction.

Cellular cap cuticle: carefully handled yet still broke in an odd direction.

Cellular cap cuticle: both wrinkling and sparking in the sun.

Panaeolus mottled gills - from spores that mature irregularly.

Panaeolus is more typically on dung, or if not, has mottled gills and is in grass. The stems are often stiffer and less likely to be white. Otherwise, see Psathyrella, below.

Psathyrella - usually found on the ground or wood, black or very dark spores, dry, hygrophanous caps, attached gills that easily come free, often white stems and very fragile fruit bodies that are hard to keep in one piece. Pieces of the cap of any shape and size may break off. Those with a partial veil usually leave material hanging off the edge of the cap instead of around the stem like a ring (except for some distinctive species). The hygrophanous caps often start dark and fade to pale tan. Some have recently been split into several new genera.

Unfortunately, there are many species, exceedingly difficult to tell apart and with little to distinguish them. Many lookalike species are not covered here.

First, here are the more delicate species, yet with a long stem. They have larger spores (>10u) than most other Psathyrellas.

P. microrhiza group - likely to have veil remnants on the cap or cap edge when young.

P. corrugis (gracilis) group - never any cap veil remnants

P. aquatica - this P. corrigus group member grows entirely underwater in S. Oregon.

Some collections of some species have pink gill faces bottoms (closest to the edge) or pink tones in the cap.

P. prona group - similar, often pinkish species with sparse veil, often in rich, fertilized soil.

Now a non-inclusive list of species with white velar material all over the cap and stem, sometimes making the stem somewhat shaggy when fresh. The cap scales easily rub off, so they may need to be observed when young. Some even have a ring!

P. longistriata group - 4 species with a ring on the stem, without purple tones.

P. subpurpurea - a ring on the stem, and purple tones in the cap.

P. caput-medusae - very stocky, very scaly cap and stem. White scales turn brown and can rub off. <5cm. Clustered.

P. maculata - margin hung with veil material, fleeting ring on stem, hairs on cap and stem become dark, <6cm.

P. 'frustulenta' - lots of shaggy white cap and stem material when fresh, smallish like P. hirta but not on dung. This may not be the correct name for this poorly understood species.

P. olympiana - <4cm, on woody debris, rusty brown fading to tan, cap margin with veil material and wrinkling in age. Stem and cap are white-fibrillose when fresh, as in P. canoceps, but the stem is thicker. Has "metuloids" like Inocybe!

Coprinopsis canoceps - a non-inking inky cap. <3.5cm, fibrillose cap and stem, but paler and/or less stocky than P. olympiana. No pleurocystidia distinguishes it.

Candolleomyces candolleanus (Psathyrella candolleana) - honey coloured, in conifer forests and near urban hardwoods, veil material on cap margin, <7cm. No pleurocystidia. Two local species, neither the real thing.

C. typhae - spring, <2cm, grows on leaves and stems near water.

P. hirta - <2.5cm, cap covered in white removable hairs, found on dung like Panaeolus, resembles P. canoceps but dark brown, fading.

P. potteri - found on dung but not scaly.

P. pennata (carbonicola) - on burnt ground, <6cm, chocolate brown fibrillose cap, fading to paler brown.

P. epimyces - grows on rotting Coprinus comatus, <6cm, white

P. ammophila - growing in sand dunes. Red brown, fading. <4cm.

P. piluliformis (hydrophila) - clusters on hardwood, <5cm, red-brown fading to tan, veil material on cap. Small spores (<6x4u).

Homophron spadiceum - also clustered on hardwoods, but stockier with paler red-brown spores. No veil material, resembles Entoloma, <6cm. With Inocybe-like metuloids.

P. sublateritia - brick red spore print, may or may not be the same species.

Britzelmayria multipedata - clusters on the ground, rooting stems that often fuse. Little veil material and larger spores than P. piluliformis.

P. bipellis - sweet smelling.

P. abieticola (subnuda/vesciculocysis) - nondescript but abundant species only identifiable microscopically.

P. praetenuis (atrifolia) - another nondescript but abundant species only identifiable microscopically.

P. rufogrisea (alluviana/barlowiana/uskensis - another genetic species with four possible names where there may only be one real species.

P. elliptispora (griseopallida) - yet another nondescript species, appearing to leave veil material on the cap margin.

Parasola conopilea - <4cm, very conical. Only recognizable as a Parasola by lack of veil and very small cap hairs.

P. longipes grp - veil remnants on cap, large conical species with large spores (>10u). Needs to move to Coprinopsis.

Coprinopsis uliginicola - <10cm, large, grey fibrillose cap, under aspen and other trees. Large spores (>10u).

Species with integrated scales that can't be removed (and possibly rough spores) aren't closely related and have been moved to other genera. Sometimes they are sturdy enough to not resemble Psathyrella.

Panaeolus - much like Psathyrella, but usually on dung (with one important exception). The gills are mottled dark and light from irregularly maturing spores. Often hygrophanous. Probably deserving of their own family.

Panaeolus foenisecii (castaneifolius) - dark brown warty spores (most others have smooth black spores). In grass, dark brown, dark band of colour around cap edge? Hygrophanous, fading. Up to 3cm. Darker stem than Psathyrella with more distant gills.

Panaeolus papilionaceus (campanulatus, sphinctrus) - in dung, bell shaped, lead colour. Up to 5cm. Veil sometimes leaves material hanging off cap margin.

P. papilionaceus var. retiruga - wrinkled cap

P. semiovatus (phalenarum, solidipes) - the species that may have a ring, but always the stockiest, stem up to 1cm wide. On dung.

P. subbalteatus grp - dark band of colour around the cap edge. No velar material. <5cm. Not bell shaped as in P. papilionaceus. On dung.

P. acuminatus - similar, slightly slimmer than P. subbalteatus, differs microscopically.

P. fimicola/ater - even slimmer, <2.5cm. P. ater (if distinct) is blackish. Needs confirmation.

P. alcis - very small on dung. <1cm. Northern species.

P. cyanescens - turns blue from Psilocybin. <4cm. On dung.