Gomphidius oregonensis

Gomphidius oregonensis, commonly known as insidious gomphidius, is a mushroom found only in western North America, most commonly on the Pacific Coast. G. oregonensis 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 common and widespread species. With age, the fruiting body becomes murky and "insidious" in appearance, hence its common name.

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-bolt" and relates to the shape of the mushroom. Oregonensis 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.

Description
At first, the cap (2–15 cm across) is convex and almost peg-like. The surface is smooth and slimy when damp. The color can vary from whitish to a dull pinkish or color of salmon flesh when young. With age, the cap becomes depressed, more viscid, and turns purplish to reddish-brown. The flesh color is soft and white or grayish.

The gills are fairly even, closely spaced and are somewhat waxy in appearance. They are white to grayish in color, turning black as ripening occurs.

The stalk is typically about 15 cm long and ranges from 1 to 5 cm in thickness. The diameter may be equal from top to bottom or tapered, appearing swollen at the base. The color transitions from a whitish shade in the upper portion above the veil to a bright yellow below.

The veil is whitish with a thread-like texture, hidden beneath a layer of slime. The veil seems to disappear as it approaches the stalk, where it forms a slimy, almost hairy ring. This ring often blackens as the mushrooms age and the spores begin to release.

The spores are smooth, spindle-shaped and elliptical, with each spore measuring 10–14 μm long, the smallest in the genus Gomphidius.

Edibility
Gomphidius oregonensis is edible, with a mild flavor and odor. Without proper preparation the mushroom is slimy in texture.

Habitat and distribution
Gomphidius oregonensis can be found in western North America, most commonly on the Pacific Coast. It is found on the ground under conifers, particularly Douglas fir. Mushrooms may be solitary or in clusters and often in colonies with G. glutinosus, and frequently with species from the genus Suillus.