Pluteus cervinus

Pluteus cervinus, commonly known as the deer shield, deer mushroom, or fawn mushroom, is a species of fungus in the order Agaricales. Fruit bodies are agaricoid (mushroom-shaped). Pluteus cervinus is saprotrophic and fruit bodies are found on rotten logs, roots, tree stumps, sawdust, and other wood waste. The species is common in Europe and eastern North America, but rare and possibly introduced in western North America.

Etymology
The species epithet, cervinus, means "deer-like"" and refers to the colour of the cap (described as "rehfarbig" in Jacob Christian Schäffer's original 1774 description).

Description
The cap ranges from 3-15 cm in diameter. Initially it is bell-shaped and often wrinkled when young. Later it expands to a convex shape. The cap can be deer-brown, but varies from light ochre-brown to dark brown, with a variable admixture of grey or black. The centre of the cap may be darker. The cap surface is smooth and matt to silky-reflective. The cap skin shows dark radial fibres when seen through a lens, indicating that the microscopic cuticle structure is filamentous. The gills are initially white, but soon show a distinctive pinkish sheen, caused by the ripening spores. The stipe is 5–12 cm long and 0.5–2 cm in diameter, usually thicker at the base. It is white and covered with brown vertical fibrils. The flesh is soft and white. The fruit body has a mild to earthy radish smell and a mild taste at first, which may become slightly bitter.

Spores are elliptical, smooth and measure approximately 7.0–8.0 × 5.0–5.5 μm. Hyphae lack clamp connections. Cystidia are thick-walled with apical projections. The spore print is pinkish brown.

Pluteus cervinus grows on rotten wood and fruit bodies can be found most commonly in the autumn. They are said to be edible when young, but considered by some to be of poor quality and not often collected for the table.

Similar species
Similar species include Pluteus atromarginatus, which has a dark brown edge to the gills; Pluteus rangifer, a subarctic species; Pluteus elaphinus in eastern North America; Pluteus hongoi which typically has a paler cap and occurs in Eurasia and eastern North America; and Pluteus exilis which typically produces fruit bodies in spring and occurs in western North America. Similarly coloured species of Entoloma have gills that are attached to the stipe (not free) and distinctive, angular spores.