Major Groups > Polypores > Stemmed, Pale-Fleshed > Polyporus varius


Polyporus varius

[ Basidiomycota > Polyporales > Polyporaceae > Polyporus . . . ]

by Michael Kuo

Typically fruiting on smaller hardwood sticks and decaying branches, this polypore is fairly easily recognized by its small size, its whitish pore surface, and its black, or half-black, central stem. It is widely distributed across North America, and appears to vary somewhat in the color and texture of its cap. Like many polypores it is rather tough, and can manage to "stay up" for quite a while in dry weather—resulting in older specimens with faded, nearly white caps and sordid brownish pore surfaces.

Polyporus badius is vaguely similar but is usually larger, redder, and shorter-stemmed. Polyporus melanopus is even more similar in appearance, but not in habitat; it grows terrestrially.

Traditionally, the name "Polyporus elegans" was applied to a mushroom slightly larger than Polyporus varius, with a radially lined cap. See Overholts (1953) or Gilbertson & Ryvarden (1987) for a full account of the difference—though even Overholts admits that "P. elegans and P. varius differ but little, except in size" (264). More recently, studies by Nunez & Ryvarden (1995) and Kruger (2002, 2006) have considered the two species to be the same. Polyporus leptocephalus is another name for this species.


Ecology: Saprobic on decaying hardwood sticks and small logs that have lost their bark; causing a white rot; growing alone or scattered; first appearing in late spring and early summer, but often collected in summer and fall; apparently widely distributed in North America. The illustrated and described collections are from Illinois, Michigan, Colorado, and Québec.

Cap: 2–6 cm; broadly convex to flat, developing a central depression; usually round in outline, but sometimes cleft or somewhat kidney-shaped; dry; bald; sometimes slightly radially lined, especially toward the margin; yellowish, tan, cinnamon tan, or paler; sometimes featuring vague concentric zones of color.

Pore Surface: Running down the stem; whitish to grayish when young, becoming dingy brownish in age; sometimes bruising faintly brownish; with 2–3 angular pores per mm; tubes to 3 mm deep.

Stem: Central or off-center to lateral; 1–2 cm long; 4–7 mm wide; tapered slightly to base; often curving; dry; bald and pale tan at the apex, becoming velvety and dark brown to black from the base upward; tough.

Flesh: Whitish to dingy yellowish; unchanging when sliced; thin; very tough.

Odor and Taste: Not distinctive.

Chemical Reactions: KOH brownish orange on flesh and cap surface.

Spore Print: White.

Microscopic Features: Spores 9–12 x 2.5–4 µm; cylindric to allantoid; smooth; hyaline in KOH. Hymenial cystidia absent. Hyphal system dimitic. Clamp connections present.

REFERENCES: (Persoon, 1796) Fries, 1821. (Overholts, 1953; Smith, Smith & Weber, 1981; Arora, 1986; Gilbertson & Ryvarden, 1987; Phillips, 1991/2005; Lincoff, 1992; Nunez & Ryvarden, 1995; Horn, Kay & Abel, 1993; Barron, 1999; Kruger et al., 2006; McNeil, 2006; Sotome et al., 2008; Kuo & Methven, 2014.) Herb. Kuo 05110307, 06140801, 06291406. Herb. DBG RMNP 2009-070, ROMO 2012 5025-27, ROMO 2012 5027-05, ROMO 5027-29, ROMO 2012 5027-34.

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Polyporus varius

Polyporus varius

Polyporus varius

Polyporus varius

Polyporus varius

Polyporus varius

Polyporus varius

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Kuo, M. (2015, April). Polyporus varius. Retrieved from the MushroomExpert.Com Web site: