Cup Fungi Bowl-shaped ascomycetes of the Pacific Northwest — open-faced, spore-bearing, and often overlooked
Cup fungi are ascomycetes — they produce spores in microscopic sacs (asci) that line the inner surface of the cup. The defining form is a bowl or disc, open-faced and oriented upward to launch spores into the air. Most are small and go unnoticed, but several PNW species reach impressive sizes and are hard to miss once you start looking.
They grow on soil, duff, and decaying wood. A few appear soon after snowmelt in mountain conifer forests. Others fruit through the wet season at lower elevations. None of the species covered here are choice edibles, but they’re worth knowing — they’re common, distinctive, and part of the spring and winter fungal landscape across Cascadia.
Explore Conifer Forests on Forayz
Several of the cup fungi here fruit under conifers, especially true fir. Use ecoregion data to find conifer forest habitat near you. Free with a Forayz account. Pro adds tree species maps.
Notable PNW Species
Pink Crown — Sarcosphaera coronaria
One of the largest cup fungi in the PNW, 3–15 (20) cm across. It begins as a hollow ball, usually hidden under the duff, with a small hole on top; the ball then tears open into a cup with a jagged, crown-like rim. The inside is pale at first and deepens to lilac or violet; the outside is whitish and rough, and usually crusted with soil. Young ones still in the duff can look like white balls. Grows under conifers, above all true fir. Common, often in quantity, east of the Cascades; on the west side it is rare and keeps to drier sites. Spring. Mildly toxic — do not eat. It likes the same east-side fir forest as “natural” morels, so it can point you to their habitat (Siegel & Schwarz, Mushrooms of Cascadia).
Pig’s Ears — Discina ancilis (= Gyromitra ancilis)
A shallow cup or disc, 2–10 (15) cm across, that gets wavier and more wrinkled as it ages. The top is cinnamon-brown to orange-brown, anywhere from smooth to heavily wrinkled; the underside is paler and often ribbed where it meets a short, thick stem. Grows on soil, duff, or well-rotted wood in conifer forest, often soon after the snow melts. Common east of the Cascades and less so on the west side. Edible when thoroughly cooked. It is a relative of the false morels; see the false morel guide.
Dissingia crassitunicata
A small bowl, 0.5–5 cm across, on a short, thick, pale stem that is ribbed and creased; the ribs may run a little way up the underside of the cup. The inside is dark: black, dark brown, or gray. Grows under conifers, especially true firs, on soil, moss, or duff. Common across the east side of the Cascades and scarce or missing on the west side. Spring and early summer. Edibility unknown. Formerly called Helvella crassitunicata.
Pseudoplectania melaena
A dark cup 2–5 (8) cm across that opens out into a wavy-edged dish. The inside is olive-black, fading toward gray-brown with age; the outside is black and thinly hairy. The stem is a black knob or up to 3 cm long. Grows on woody debris and the duff around it, and is common, especially west of the Cascades. Midwinter into spring. Edibility unknown. Several other black cups look similar (Pseudoplectania nigrella, Plectania milleri, Donadinia nigrella), and separating them can take a microscope.
Urnula padeniana
A large black cup, 5–12 cm across, whose rim curls inward at first before the cup opens out, sometimes to a flat disc. The inside is dull black when dry and shiny when wet; the outside is dark gray to black, velvety, and often wrinkled. The stem is black, stout, 2–8 cm long, and narrows toward the base. Its flesh is the giveaway: thick and rubbery around a jelly-like core, translucent gray when young. Grows on buried wood or duff; common and widespread. At low elevations it fruits in winter and early spring, on the east side of the Cascades in spring and early summer. Edibility unknown. The smaller Pseudosarcosoma latahense is almost identical. Formerly called Sarcosoma mexicanum.
Layered Cup — Peziza varia
A pale brown cup, 3–12 cm across, that soon spreads out and turns ragged at the edge. The inside is smooth, light ocher to light brown. The flesh is thin and brittle; under a hand lens it shows several distinct layers (MycoMatch). Usually in clusters on rotting wood, rich soil, or wood chips, and occasionally indoors in basements (Arora). Widespread and common. Fruits through the wet season, most of all in spring. Edibility unknown. Peziza is a large genus with many similar brown-cupped species — microscopy is often needed for confident species-level identification.
Spores in Sacs, Not on Clubs
Cup fungi are ascomycetes: their spores develop inside microscopic sacs called asci, which line the inner surface of the cup. When mature, the asci burst and release spores — sometimes visibly, in a faint puff. This is fundamentally different from gilled mushrooms and polypores (basidiomycetes), which produce spores on the outside of specialized cells. The distinction matters because it puts cup fungi in a completely different branch of the fungal tree.
Sarcosphaera Is Mildly Toxic
Sarcosphaera coronaria is mildly toxic (Siegel & Schwarz) and should not be eaten. If you find a large, crown-shaped purple cup breaking out of the duff under fir — admire it, photograph it, leave it.
Track Spring Conditions
Many cup fungi fruit soon after snowmelt. Use the soil temperature, snow, and rainfall layers on Forayz to track when conditions are right in mountain conifer forests. Free with a Forayz account.
Habitat & Season
Most PNW cup fungi are tied to conifer forests. Sarcosphaera, Gyromitra ancilis, and Dissingia are all spring fruiters associated with true fir and other conifers, most common east of the Cascades where they appear soon after snowmelt. Pseudoplectania fruits earlier, from midwinter into spring, mostly west of the Cascades; Urnula fruits in winter and early spring at low elevations and later on the east side. Peziza is the generalist, appearing on disturbed soil, wood chips, and rich ground throughout the wet season.
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.