What You Should Know
Crepidotus variabilis is a tiny, kidney-shaped fungus that appears on dead twigs of broad-leaved trees in autumn and winter. Common in woodlands, this mushroom occurs across mainland Europe and is also recorded in many other parts of the world including North America.
Other names: Variable Oysterling.
Crepidotus variabilis Mushroom Identification
The cap is initially white, turning creamy-ochre with age. The fruitbody is nearly always laterally attached to its substrate - usually small twigs - via its cap, rather than with a stem. Typically 0.5 to 2cm in diameter and often slightly lobed.
The gills, which radiate from the point of attachment, are moderately crowded. White at first, they gradually turn yellow-brown or buff.
Almost invariably this little woodland mushroom has no stipe (stem) at all.
Ellipsoidal, ornamented with minute spiny warts, 5-7 x 3-3.5um.
Clavate, sometimes branched, 20-25 x 5-12Î¼m.
Odor and Taste
Saprobic, on twigs in deciduous and mixed woodland and at the bases of hedgerows.
August to December in Britain and Ireland.
Crepidotus variabilis Look-Alikes
Has a scalloped margin and its spores are sub-globose rather than ellipsoidal.
Is larger and its cap has small scales on an ochre background.
Crepidotus variabilis Taxonomy and Etymology
The variable oysterling was described in 1799 by Christiaan Hendrik Persoon, who established its basionym when he gave it the binomial scientific name Agaricus variabilis. It was German mycologist Paul Kummer who, in 1871, transferred this species to the genus Crepidotus, whereupon it acquired its currently accepted scientific name Crepidotus variabilis.
The generic name Crepidotus comes from crepid- meaning a base, such as a shoe or a slipper (although some sources state that it means ;cracked'), and otus, meaning an ear - hence it suggests a 'slipper-like ear'. In the past mushrooms in this genus were sometimes referred to as slipper mushrooms. The specific epithet variabilis means, as you might expect, variable. These little mushrooms are indeed very variable in shape, depending on where they are attached to their substrate; for example, they can form neat semicircular brackets on the sides of twigs and branches or almost perfectly circular fans when growing underneath a dead branch.
Crepidotus variabilis Synonyms
Crepidotus variabilis trichocystis Hesler & A. H. Sm., 1965
Crepidotus variabilis stercorarius Reichert & Aviz.-Hersh., 1959
Crepidotus variabilis subsphaerosporus J. E. Lange, 1938
Crepidotus multiformis Murrill, 1917
Crepidotus variabilis duriusculus Sacc., 1880
Crepidotus variabilis variabilis (Pers.) Gillet, 1876
Crepidotus variabilis variabilis (Pers.) P. Kumm., 1871
Crepidotus variabilis acerinus Lasch, 1829
Crepidotus variabilis albidus (Balb.) Fr., 1821
Crepidotus variabilis vulgaris Alb. & Schwein., 1805
Crepidotus albidus Balb., 1804
Crepidotus variabilis sinuatus (Pers.) Pers., 1801
Crepidotus sinuatus Pers., 1800
Photo 1 - Author: Jason Hollinger (Attribution 2.0 Generic)
Photo 2 - Author: Jason Hollinger (Attribution 2.0 Generic)