Gomphidius oregonensis

What You Should Know

Gomphidius oregonensis is a mushroom found only in western North America, most commonly on the Pacific Coast. It can be distinguished by its spores which are the shortest in the genus, typically less than 14 µm long. Earlier in growth, G. oregonensis can be difficult to distinguish from other members of the genus Gomphidius, such as G. glutinosus which is the most widespread species. With age, the fruiting body becomes murky and rather insidious in appearance, hence its common name.

It is most certainly edible, but with its slimy texture and unattractive appeal, it is not recommended. It has some use in the culinary field but lacks value overall for edibility.

Other names: Clustered Gomphidius, Insidious Gomphidius.

Gomphidius oregonensis Mushroom Identification

1. Ecology

   Mycorrhizal with conifers, especially Douglas-fir; typically growing in clusters, but not infrequently growing alone or scattered; fall and winter; West Coast to Idaho and Montana.

2. Cap

   3–10 cm wide; convex, becoming planoconvex; bald; slimy; streaked; pale pinkish to brownish when young, becoming dark reddish-brown to dark brown, or sometimes fading to tan; spotting and discoloring blackish to black in places or overall with age.

3. Gills

   Running down the stem; close; pale buff at first, becoming smoky gray; short-gills frequent.

4. Stem

   5–10 cm long; 1–2 cm wide; tapering to base; often rooting; with a fibrillose partial veil that is typically poorly developed and hard to distinguish underneath the slime veil; at maturity slimy over the lower portion; sometimes adorned with a ring or ring zone that becomes blackened by spores; whitish above, dull to bright yellow below; discoloring and bruising black.

5. Flesh

   White in the cap; yellow in the stem.

6. Odor and Taste

   Not distinctive.

7. Spore Print

   Purplish gray to black.

8. Microscopic Features

   Spores 11–13 x 4–5 µm; fusiform or narrowly ellipsoid; smooth; brownish in KOH. Hymenial cystidia to 125 x 12.5 µm; cylindric to narrowly fusoid; thin-walled; hyaline in KOH. Pileipellis an ixocutis. Clamp connections not found.

Gomphidius oregonensis Look-Alikes

1. Gomphidius smithii

   Differs in that the cap is light pinkish without dark discolorations and the flesh within the lower part of the stem is not yellow, except sometimes at the end.

2. Chroogomphus vinicolor

   Is recognized by a viscid to a glutinous cap, often spotted black in age, conspicuously decurrent, gills, and a yellow stem base.

3. Gomphidius glutinosus

   Is very similar but tends to be more solitary in its fruiting and has a stipe that is usually not as deeply buried in the substrate. A check of spore size, however, is often required to confirm identification.

4. Gomphidius subroseus

   Has a cap, which as the species name suggests, has rose-pink tones.

5. Gomphidius maculatus

   Lacks a veil and is particularly associated with larch.

Gomphidius oregonensis Taxonomy

Gomphidius oregonensis was first described in 1897 by botanist Charles Horton Peck. The genus name is derived from the Greek γομφος, gomphos, meaning "nail" and relates to the shape of the mushroom. Oregonensis simply pertains to the area in which the species was first observed. Orson K. Miller made it the type species of the section Microsorus in the genus Gomphidius.

Sources:

Photo 1 - Author: Corvi Zeman (Creative Commons Attribution 4.0 International)

Photo 2 - Author: Ron Pastorino (Ronpast) (Creative Commons Attribution-Share Alike 3.0 Unported)