Sarcodon scabrosus

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by Michael Kuo

In theory, "Sarcodon scabrosus" is a widely distributed species in Europe and in North America, recognized by its brown to reddish brown or purplish brown colors; its appressed cap scales, which develop as the mushroom matures; its greenish to bluish or black stem base; its bitter taste; and, under the microscope, its lack of clamp connections. However, the reality is that Sarcodon scabrosus is a northern European species apparently mycorrhizal with pines (species of Pinus)--and it may or may not actually occur in North America, where we have a rather bewildering assortment of scabrosus-like mushrooms that differ slightly in morphology and that have evolved with widely different ecosystems and mycorrhizal hosts (see the comments below).

Description:

Ecology: As a species group, mycorrhizal with conifers and hardwoods; growing alone or or gregariously; summer; widely distributed in North America.

Cap: 3-10 cm wide; convex to broadly convex with a central depression; dry; when young appressed-hairy to sub-scaly; with maturity developing well defined scales with darkened tips; reddish brown to purplish brown; the margin often inrolled.

Undersurface: Running down the stem; covered with crowded spines or "teeth" that are 2-8 mm long; pale brown with whitish tips at first, becoming darker brown overall with age.

Stem: 4-10 cm long; 1-2.5 cm thick; often tapered to the base, which frequently extends into the ground like a root; dry; fairly smooth, except where punctuated by aborted spines; pale or brownish; base with prominent white to pink mycelium over a greenish to bluish or black ground color.

Flesh: Whitish to pinkish; gray to black or greenish in stem base; soft.

Odor and Taste: Taste bitter (sometimes developing slowly); odor mealy, or not distinctive.

Chemical Reactions: Flesh and cap surface at first green with KOH, then resolving to gray.

Spore Print: Brown.

Microscopic Features: Spores 5-7.5 µ; irregularly globose to subglobose; nodulose. Clamp connections absent.

REFERENCES: (Fries, 1836) Karsten, 1881. (Saccardo, 1891; Maas Geesteranus & Nannfeldt, 1969; Smith, Smith & Weber, 1981; Arora, 1986; Baird, 1986a; Baird, 1986b; Harrison & Grund, 1987a; Barron, 1999; Roody, 203; McNeil, 2006.) Herb. Kuo 07180710, 07210701, 07220702, 07230805.

Hydnum scabrosum is a synonym.

Descriptions of Sarcodon scabrosus vary widely in North American literature, and competing taxon names include Sarcodon fennicus and Sarcodon underwoodii. The former is a Finnish species recognized in North America by some authors, including Smith, Smith & Weber (1981), who separate it from Sarcodon scabrosus on the basis of its not turning green in KOH; and Harrison & Grund (1987a), who say that it does turn green in KOH, but that its stem base is not greenish. Sarcodon underwoodii, according to Baird (1986b), is a hardwood-associated species with a yellow-brown cap, extremely bitter taste, and a stem base that does not develop green shades. Harrison and Grund agree on the cap color, hardwood habitat, and very bitter taste, but say Sarcodon underwoodii does have a green stem base. They maintain that Sarcodon scabrosus is associated only with conifers. Extensive molecular and ecological study of many well documented North American collections is obviously needed.

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Cite this page as:

Kuo, M. (2009, February). Sarcodon scabrosus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/sarcodon_scabrosus.html