They are usually found on the ground but are saprophytic (often growing on debris or cones) and belong to the Marasmioid clade unless otherwise specified.
Collybia - When Collybias were found to not be all related to each other and the larger ones were split into Gymnopus and Rhodocollybia, it was unfortunately the atypically small Collybias that got to keep the name, simply because they had the name first, creating confusion. So "collybioid stature" really means big like things Collybia used to be, not small things like Collybia is now. On behalf of mycologists everywhere, I apologize. They are not related to Marasmius and Gymnopus, but to the Tricholomatoid clade. In fact they are very closely related to Clitocybe. (Very. Unfortunately, they may actually be Clitocybes, which doesn't help the confusion any).
These can be recognized by their small size (<1cm),
preference for growing on old rotting
mushrooms (often an old Russula turned into an
unrecognizable black pile of goo), closely spaced gills and by often having sclerotia at the base of
the stem - a tight little pill ball of nutrients. The caps and stems are pale and not tough
so they are most likely to be confused with Strobilurus/
Dendrocollybia racemosa - <1cm, you can't miss the branches all over the stem of this rare little gem, where asexual spores are produced. It has round, black sclerotia and also grows on old rotting Russulas. Sometimes it is capless.
Asterophora - growing on decaying
A. parasitica - true gills, not dusty, wider spaced gills than Collybia, which it is most likely to be confused with.
S. trullisatus (left) - orange two-toned stem. Pale cap perhaps grey or orangish. Gills not crowded. Doug fir cones. Fall.
B. myosura (right) - uniform pinkish stem. Crowded gills.
S. occidentalis - slightly darker cap than S. trullisatus on spruce cones, fall or spring. Two-toned orange stem.
Gymnopus - the bulk of the genus Collybia were moved here. They typically grow up to 5cm across, unless otherwise specified. They can sometimes be found on wood and can therefore be confused with the mushrooms found here. Some are somewhat hygrophanous. They do have cartilaginous stems and tough fruiting bodies that are not very fleshy and don't rot quickly. They are sometimes confused with Rhodocollybia, which are usually a bit larger and fleshier.
I sometimes find different, unidentifiable species of Gymnopus. More of them may be hiding out there.
G. acervatus - big clusters, reddish stems and young caps. Some have erected a new genus for this, Connopus.
G. confluens - pale (sometimes darker when fresh), finely hairy stem, more crowded gills than G. peronatus.
G. striatipes - more distant gills and grooved stem.
G. dryophilus - brighter orange, bald stem, usually smaller than R. butyracea.
G. fuscopurpureus - dark even in the gills, with hairy stem base. KOH turns dark.
G. putillus - red-brown cap and gills, white stem, KOH negative.
G. villosipes - similarly dark cap and young gills, umbilicate cap?, entirely pubescent stem, KOH negative.
G. peronatus - one of the most common mushrooms of all, recently introduced! Yellowish, hairy stem base. Taste hot (but not always? Sometimes lemony.)
G. polyphyllus - cap and stem dark or pale, crowded gills, smells strongly of garlic, bigger than Marasmius.
Rhodocollybia - usually just a bit bigger and stockier than Gymnopus (whose stems are more cartilaginous), they are best defined by a slight tinge of yellow, orange or pink to the spores, but not at all deep and dark enough to qualify as pink-spored mushrooms. It's too subtle to notice unless you take a spore print, so you may just have to learn to recognize them. Somewhat hygrophanous. Most often with serrated gill edges, and slightly rooting stems.
Gymnopus luxurians, above, is the size of a Rhodocollybia, but doesn't have the same greasy look that Rhodocollybia often does.
R. butyracea - pale to dark orange brown, stockier than G. dryophilus with serrated gill edges.
R. badiialba - usually dark, more crowded gills, longer rooting stem.
R. extuberans (unakensis) - poorly understood similar dark species.
R. oregonensis - dark two-toned cap, with the longest rooting stem. Also spotting red and definitely smells like marzipan!
R. subsulcatipes - paler brown cap, but darker brown stem.
Melanoleuca - They are best recognized by
often having a very elegant Amanita/
Distinctively, they have amyloid warty spores (that turn dark in iodine) and often have cystidia of the "stinging hair" type - narrow and encrusted. You can't trust some of these species names, because like Lyophyllum, they have never been thoroughly studied in North America!
The fall species may be the same or different (M. melaleuca, M. graminicola, M. stridula or none of the above). These lack "stinging" cystidia.
M. 'humilis' ('melaleuca') - dark cap, short grey stem, with "stinging" cystidia. Nobody can agree on whether or not M. melaleuca has cystidia.
M. cf. subbrevipes - large (12cm), yellow-brown, lacking encrusted cystidia. A smaller yellowish species perhaps with encrusted cystidia resembling M. brevipes has been found in lawns.
M. verrucipes - This confused us a while ago when it was first introduced from Europe. White, with black scabered stem.
Lyophyllum - part of a separate family in the Tricholomatoid clade, these miscellaneous mushrooms can be tricky to identify, as they are mostly grey without anything very distinctive. As with Melanoleuca they have variably attached gills (which makes them easily confused with Clitocyboid mushrooms when the gills are decurrent), a non-viscid greasy to hygrophanous cap, and no partial veil, but they do not have as distinctive a stature as Melanoleuca. The most common groups of Lyophyllums do have distinctive traits, luckily. Usually in the 5-12cm range. They are mycorrhizal.
There are rumours of a whole lot of other Lyophyllum species (that don't cluster and do not turn black) with little that is distinctive about them and therefore very hard to ID. They have never been studied in the PNW!
L. semitale grp - smells farinaceous and eventually turns black wherever handled. Not clustered. Rumored to be 18 species in this group!
Rugosomyces (formerly Calocybe) - known as the colourful Lyophyllums. Their pretty colours make them distinctive. Not usually hygrophanous. Usually <5cm.
Lyophyllum onychinum - a gorgeous purple-red cap and golden gills, larger. Actually a Lyophyllum even though it is brightly coloured.
Tephrocybe, etc. - difficult to ID small (usually <2.5cm) mushrooms also related to Lyophyllum. The caps are hygrophanous. They are parasitic and have spiny spores. (T. rancida is not parasitic, has smooth spores, is not related and will need a new name). The others are related, but have been given new names by some. Ironically, none of these will be left in Tephrocybe. They can be mistaken for Mycena, Rhodocybe or a host of other things.
T. tylicolor (Sagaranells tylicolor) - notched, on the ground, rotting flesh or feces. Mushroom without strong odor.
T. rancida - grey with a whitish bloom, strongly rancid, notched, long rooting stem. Not related, possibly more related to Termitomyces. <5cm.
Other miscellaneous collybioid mushrooms:
Marasmius oreades - found in grass in the spring. <5cm. Tough but not wiry stem. Often wavy cap, sometimes uplifted margin. Famous for sometimes growing in fairy rings.
Callistosporium luteoolivaceum - <5cm. Greasy olive yellow-brown cap and stem. Usually growing from wood, but sometimes buried. The stem is not cartilaginous. Probably in the Tricholomatoid clade. Hard to recognize, but turns red in KOH. Not hygrophanous.
Macrocystidia cucumis - <5cm. I call this the sushi mushroom, because it actually smells like fish and cucumber, with a hint of rice. OK, I'm joking about the rice. The spores are pinkish, so you might look for it in pink spored attached gilled Entoloma, but it is in fact related to Pluteus. Hygrophanous. In gardens.
Pseudolaccaria (Pseudoomphalina) pachyphylla - difficult to ID. The
odor is variable (slightly farinaceous
|Omphaliaster asterosporus is a similar darker grey-brown mushroom found in moss, resembling the more common Arrhenia. They have a hygrophanous, striate, umbilicate cap without waviness and short decurrent gills. However, Omphaliaster is farinaceous and it is most confidently identified by its startlingly nodulose spores. It is also a member of the Tricholomatoid clade.|
Some Mycenas can be unusually large or not conical. Make sure you don't have one of those.
M. pura - quite large (M), cap flattens in age, purple fading to grey, smells of radish. I've seen blue and albino versions.
M. pearsoniana - very similar.
M. maculata - on wood, developing reddish spotting. Other large brownish-grey species exist too.
Collybia, Gymnopus and Rhodocollybia are covered online at