Gilled Mushrooms The largest and most varied group of mushrooms in the Pacific Northwest
Gilled mushrooms (agarics) make up the vast majority of what people picture when they think “mushroom.” They share a basic structure: a cap supported by a stem, with thin blade-like gills on the underside that produce spores. Beyond that shared body plan, the diversity is enormous.
The PNW is home to hundreds of gilled species. They range from prized edibles like matsutake and oysters to deadly Amanitas, and from tiny, fragile Mycena to dense clusters of honey mushrooms (Armillaria). (Chanterelles have blunt ridges rather than true gills; see the veined mushrooms page.) Identification within this group often requires careful attention to spore print color, gill attachment, habitat, and sometimes microscopy.
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Use ecoregion data and public land overlays to scout gilled mushroom habitat across Oregon and Washington. Free with a Forayz account. Pro adds tree species maps.
How Gilled Mushrooms Work
Gills are the primary spore-producing surface in this group. Each gill is lined with millions of microscopic spore-bearing cells (basidia) that release spores into the air currents between adjacent gills.
Gill attachment to the stem is one of the first things to check when identifying an unknown species. Free gills don’t touch the stem at all (Amanita, Agaricus). Attached (adnate) gills connect squarely to the stem. Decurrent gills run down the stem (oyster mushrooms). Notched (sinuate) gills have a small scoop before meeting the stem (Tricholoma). Spore print color is one of the first steps in identifying an unknown gilled mushroom — it splits the possibilities into broad groups before you consider anything else.
Major Groups in the Pacific Northwest
| Group | Key Traits | Edibility | Notable PNW Species |
|---|---|---|---|
| Amanita | White spore print. Free gills. A universal veil leaves a volva (cup) at the base; most also have a ring, but the grisettes don’t. | Contains both edible and deadly species. Never eat without expert-level ID. | A. phalloides (Death Cap), A. muscaria, A. pantherina, A. pachycolea |
| Russula & Lactarius | Brittle flesh that snaps cleanly. Russula: no milk. Lactarius: exudes latex when cut. | Mixed — many edible, some cause GI distress. | R. brevipes, L. rubidus (Candy Cap), the L. deliciosus group (several PNW species, none of them the European L. deliciosus) |
| Cortinarius | One of the largest genera in the PNW. Cobweb-like partial veil (cortina). Rust-brown spore print. | Assume toxic unless expert-identified. Some are deadly (C. rubellus). | C. violaceus, C. traganus, C. croceus group |
| Tricholoma | Stout, fleshy. Notched gill attachment. White spore print. Mycorrhizal with conifers and hardwoods. | T. murrillianum (Matsutake) is highly prized. Others range from edible to toxic; T. pardinum causes severe gastrointestinal poisoning. | T. murrillianum, T. saponaceum, T. pardinum |
| Armillaria (Honey Mushrooms) | Dense clusters on wood or roots. Ring on stem. Rhizomorphs (black “shoelaces”). | Edible when well cooked, though some people get gastrointestinal upset (Volk, Benjamin). Must be distinguished from the deadly Galerina marginata. | A. ostoyae, A. nabsnona |
| Pleurotus (Oyster Mushrooms) | Shelf-like, offset or absent stem. Decurrent gills. White to lilac-gray spore print. Mostly on hardwoods. | Edible and excellent. | P. ostreatus, P. pulmonarius |
| Mycena | Tiny, fragile, often on wood or duff. Conical to bell-shaped caps. | Not worth eating; M. pura is possibly poisonous (it contained muscarine in one study, Arora). | M. haematopus (bleeds red), M. pura |
| Hygrocybe / Gliophorus (Waxy Caps) | Waxy, thick, widely spaced gills. Often brightly colored. In moss, duff, and soil, often under western redcedar at low elevations west of the Cascades; late fall and winter (Siegel & Schwarz, Mushrooms of Cascadia). | Small and not commonly collected. The witch’s hat (H. conica) is possibly poisonous (Arora). | The red H. coccinea group and the green-to-orange G. psittacinus group (Parrot Mushroom) — both PNW groups hold several species that differ from the European ones |
| Psathyrella / Coprinoid | Dark spore prints. Fragile. Often in disturbed soil or on wood. Some autodigest (ink caps). | See Ink Cap guide — shaggy mane is the one most widely eaten. | Coprinus comatus, Coprinellus micaceus |
Spore Print Color Is Your Starting Point
Place a cap gill-side down on paper for a few hours or overnight. White, cream, pink, brown, purple-brown, rust, or black — the color immediately narrows the possibilities and is essential for safe identification.
Deadly Gilled Mushrooms Grow in the PNW
Amanita species cause the vast majority of fatal mushroom poisonings worldwide, and the worst of them grow here. The death cap (A. phalloides) turns up in PNW towns and suburbs, often near planted hardwoods. White destroying angels (A. ocreata and close relatives) are rarer, found in lowland hardwood areas (D. Miller). The small brown Galerina marginata, which grows on wood, carries the same deadly toxins (amatoxins). Never eat a gilled mushroom with white gills, a ring, and a cup at the base, or any small brown mushroom on wood, without expert identification.
Habitat & Season
Gilled mushrooms occupy every habitat in the PNW. Mycorrhizal species (Amanita, Russula, Cortinarius, Tricholoma) grow in partnership with living trees. Decomposers (Mycena, Pleurotus, Psathyrella) break down dead wood and duff, and honey mushrooms (Armillaria) both attack living trees and rot dead wood. Some are urban specialists (Agaricus, Coprinus). Most fruit in fall when rains return, but spring brings a variety of small garden-dwellers, spring Agaricus, and oysters on logs and stumps. Others, such as the waxy caps, fruit mainly in late fall and winter, and some can appear almost any month in mild, wet weather.
Track Fruiting Conditions in Real Time
Use rainfall, soil moisture, and soil temperature layers on Forayz to anticipate when fall fruiting season begins at your favorite spots. Free with a Forayz account.
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; Danny’s DNA Discoveries and the PNW Pictorial Key (© Danny Miller).