Stereoid fungus, usually annual, resupinate to effused-reflexed (possibly sessile); fruitbodies small or confluent and forming large patches; cap or protruding edge up to 1.5 cm wide, 1–2 mm thick, tough, umbonate when young; upper surface velvety, matted-tomentose to strigose-hirsute, zoned, sulcate (grooved), grayish to pale brown, with black zone beneath the tomentum, may be green in age with algae; hymenium smooth or with scattered bumps (tropical specimens may be somewhat irpicoid or shallowly poroid), color grayish yellow, brownish gray, light brown to dull violet, often with pink or violaceous tinges when fresh; growing margin white. Microscopic characters include a dimitic hyphal system of clamped generative hyphae mixed with skeletal hyphae; hymenium with large, acute, thick-walled (metuloid) cystidia that are encrusted; basidiospores ellipsoid (ovoid to cylindrical), smooth, hyaline, non-amyloid, thin-walled, 8–16 × 5–8 µm.
The cystidia are huge, long-pointed, scattered to dense, and can be seen protruding from the hymenium when viewed under a dissecting scope.
The upper surface resembles Trametes hirsuta (a bracket with pores) but the black zone beneath the hairs may show as thin black zone lines similar to those of Trametes versicolor. Punctularia strigosozonata is darker brown, upper surface velvety, and hymenium has non-protruding dendrohyphidia instead of large protruding cystidia. Stereum is similar but lacks clamp connections and the spores are amyloid.
White rot of hardwoods (angiosperms), particularly elm (Ulmus), box elder (Acer negundo) and mulberry (Morus).
Starts growing in spring or summer and can be found into the winter.
Worldwide though more common in North and South America. Widespread in North America, throughout the eastern states.
Chicago Region status
Rare. The first identified Chicago area collections were from McHenry County and Cook County in 2014. There are likely more specimens, but so far only two more have been identified (during 2015 by Leacock and Nakasone), one for 2004 and one for 2005, both from Shabbona Lake State Park. MyCoPortal lists specimens from central and southern Illinois.
Chicago Region: Illinois, Cook County, P.R. Leacock 12216, 2014; DeKalb County, W.C. Gaswick 557, 2004, and P.R. Leacock 7047, 2005; McHenry County, P.R. Leacock 11612 in 2014; PRL 13623 in 2018.
Midwest: Illinois, Lawrence County, A. D. Parker, 1972; Wisconsin, A. D. Parker, 1977.
C. L. Shear, New York Fungi 313, Stereum neglectum, New York, 1894, on decaying log of Ulmus americana.
E. Bartholomew, Fungi Columbiani 2337, Peniophora cinerascens, Kansas, 1906, on bark of dead Acer negundo.
E. Bartholomew, Fungi Columbiani 4648, Peniophora cinerascens, Georgia, 1914, on bark of Acer negundo.
This species seems obscure because it is treated in few field guides or mushroom websites, and does not have an English Wikipedia page.
There is a 1969 Burdsall specimen posted on Mushroom Observer and iNaturalist.
Ryvarden (2010) says clamps rather scattered and often difficult to find. This is certainly true. The generative hyphae don't rehydrate well and are difficult to tease apart and the septa and clamps are rare. But the cystidia are very noticeable.
Taxon Details and Links
Lophariacinerascens(Schwein.) G. Cunn.,
Transactions and Proceedings of the Royal Society of New Zealand 83 (4): 622 (1956)
Transactions of the American Philosophical Society 4 (2): 167 (1832)
Schweinitz collection, on trunk of half dead Morus alba [white mulberry], Bethlehem, Pennsylvania, USA.
Starting out in Thelephora (1832), this species has been transferred to Hymenochaete (1846), Corticium (1888), Peniophora (1888), Stereum (1890), Lloydella (1901), and finally Lopharia (1956).
Lopharia cinerescens is an orthographic variant spelling. This species has up to a dozen heterotypic synonyms dating from 1860 to 1914. Index Fungorum and Mycobank did not agree on the status of Lopharia mirabilis but it is a separate species.
Liu et al. (2018) found that a Mississippi collection, FP-105043 (listed as L. cinerascens in Justo and Hibbett, 2011) comes out as a separate species in the phylogeny.