|Major Groups > Polypores > Phellinus robiniae|
by Michael Kuo
This beautiful polypore can be found wherever black locust and closely related trees are common. It is a tough, perennial mushroom that features a brown to blackish, cracked and furrowed cap--and a beautiful brown pore surface that takes on strikingly different shades from different viewing angles. Under the microscope, it lacks setae, and features broadly ellipsoid to nearly round spores that are reddish brown in KOH.
Ecology: Parasitic on the heartwood of living trees in the genus Robinia (primarily black locust and New Mexican locust)--and saprobic on the dead wood of these trees; occasionally reported on other hardwoods (but if the host is oak see Phellinus everhartii and if the host is walnut see Phellinus weirianus); causing a white rot; perennial; growing alone or gregariously; widely distributed where the host trees occur (below the Great Lakes, and in the Southwest).
Cap: Up to 40 cm across and 20 cm deep; more or less semicircular, irregularly bracket-shaped, or kidney-shaped; flattened-convex, becoming convex, then more and more hoof-shaped with age; sometimes finely velvety, especially when young or along the margin; with age becoming cracked and concentrically furrowed; brown to dark brown or black; often hosting algae and/or moss with age.
Pore Surface: Brown; often appearing lighter or darker from different viewing angles; with 7-8 circular pores per mm; tube layers usually fairly clearly distinct, up to 9 mm deep.
Flesh: Reddish brown to orange-brown or yellow-brown; woody.
Odor: Fragrant when fresh.
Chemical Reactions: KOH instantly black on flesh.
Microscopic Features: Spores 5-6 x 4.5-5 µ; smooth; broadly elliptical to subglobose; reddish brown in KOH; inamyloid. Setae absent. Hyphal system dimitic.
Phellinus rimosus, in the sense of some authors, is a synonym. Phellinus robiniae may more properly belong to the genus Fulvifomes (see Wagner & Fischer, 2002), but a formal transfer has not been made.
Cite this page as:
Kuo, M. (2010, February). Phellinus robiniae. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/phellinus_robiniae.html