Pluteus chrysophaeus

Description

Pluteus chrysophaeus is a wood-rotting fungus that occurs mainly on elm. Its mustard-yellow cap is a distinctive feature of this relatively uncommon but very attractive little mushroom, which is generally considered inedible.

Although it is widely distributed in North America and mainland Europe. It is uncommon from the Rocky Mountains westward.

North American collections of this species have often been labeled "Pluteus admirabilis" or "Pluteus chrysophaeus."

Common names: Yellow Shield, Yellow Pluteus.

Mushroom Identification

1. Ecology

   Saprobic on the deadwood of hardwoods or, more rarely, conifers; causing a white rot; growing alone or gregariously on stumps and logs; late spring through early fall; widely distributed in North America, but much more common east of the Rocky Mountains.

2. Cap

   1-2.5 cm; broadly conic when young, becoming broadly convex to flat, sometimes with a central bump; moist; bald; when young sometimes centrally wrinkled or veined; the margin sometimes finely lined; bright yellow when young, dull yellow or brownish yellow in age.

3. Gills

   Free from the stem; close or crowded; short-gills frequent; whitish at first, becoming pinkish.

4. Stem

   2-5 cm long; 1-3 mm thick; equal; fragile; bald; pale yellow; basal mycelium white.

5. Flesh

   Insubstantial; yellowish.

6. Odor and Taste

   Odor is somewhat bleachlike when crushed; taste similar, or not distinctive.

7. Spore Print

   Pink.

8. Microscopic Features

   Spores 5-7 x 4.5-6 µ; subglobose to widely ellipsoid or sublacrymoid; smooth; hyaline in KOH; inamyloid. Pleurocystidia is widely lageniform, with or without an extended neck; 30-60 x 10-20 µ; thick-walled; hyaline in KOH. Cheilocystidia similar to pleurocystidia, or more or less clavate. Pileipellis hymeniform; elements hyaline to yellowish in KOH.

Look-Alikes

1. Pluteus leoninus

   Larger and its cap is golden yellow with a darker center.

2. Pluteus cervinus

   Has a larger, brown cap.

History

Originally described in 1762 by Jacob Christian Schaeffer, who gave it the binonial scientific name Agaricus chrysophaeus. In 1872 it was transferred to the genus Pluteus by Lucien Quélet.

Synonyms of Pluteus chrysophaeus include Agaricus chrysophaeus, Pluteus luteovirens Rea, Pluteus galeroides P. D. Orton, and Pluteus xanthophaeus P. D. Orton. Many older field guides refer to the Yellow Shield as Pluteus luteovirens.

Note: Increasingly this species is becoming known as Pluteus chrysophlebius (Berk. & MA Curtis) Sacc., but at the time of writing the FRDBI is still using the name Pluteus chrysophaeus.

Pluteus, the genus name, comes from Latin and means a protective fence or screen - a shield for example.

The specific epithet chrysophaeus is derived from the Greek prefix chruso- meaning gold or golden, and phaeus meaning dusky.

Photo sources:

Photo 1 - Author: Tatiana Bulyonkova from Novosibirsk, Russia (CC BY-SA 2.0)

Photo 2 - Author: Tatiana Bulyonkova from Novosibirsk, Russia (CC BY-SA 2.0)

Photo 3 - Author: Tatiana Bulyonkova from Novosibirsk, Russia (CC BY-SA 2.0)

Photo 4 - Author: Tatiana Bulyonkova from Novosibirsk, Russia (CC BY-SA 2.0)

Photo 5 - Author: Nina Filippova (CC BY-SA 4.0)