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Armillaria tabescens

[ Basidiomycetes > Agaricales > Marasmiaceae > Armillaria . . . ]

Taxonomy in Transition: ... Agaricales > Physalacriaceae Clade > Armillaria

by Michael Kuo

The ringless honey mushroom is the most easily identified North American species of Armillaria. It grows in clusters on hardwoods in eastern North America, from about the Great Lakes southward, and west to Texas and Oklahoma. It has no ring or ring zone on its stem, and it is usually a dull, tawny brown, though yellowish collections are not uncommon. The cap surface bears small brownish scales (at least when young), and the stem bases are fused together and somewhat pointed.

In my area (central Illinois) Armillaria tabescens is a prolific late summer and early fall mushroom. It almost always appears several weeks before Armillaria mellea, and can be seen in large clusters on lawns following heavy rains--or even in dry periods. It pops up quickly--seemingly overnight--and often appears terrestrial, though it is actually growing from buried roots.


Ecology: Parasitic and/or saprobic on hardwood roots, especially those of silver maple and oaks. I have examined trees attacked by Armillaria tabescens several times, and have never found the black rhizomorphs characteristic of Armillaria mellea in wood or bark above ground. Armillaria tabescens, as I have seen it, fruits directly from roots and rootlets, attached to them with white mycelial fuzz. The mushrooms typically appear in large clusters at the bases of trees (when the clusters appear to be terrestrial they are actually growing from underground wood) in late summer and fall, east of the Rocky Mountains.

Cap: 1-6 cm across at maturity; convex at first, becoming broadly convex or flat in age; dry; tan to tawny brown or cinnamon brown--or sometimes yellow to yellowish; when young covered with darker brown scales, but at maturity the scales are often concentrated near the center and vaguely radially arranged; the margin often becoming slightly lined.

Gills: Running down the stem or nearly so; close or nearly distant; whitish with pinkish hints; sometimes bruising or discoloring slightly pinkish to brownish.

Stem: 5-20 cm long; 0.5-1.5 cm. thick; tapering to base; bald and pale near apex, darker and nearly hairy below; without a ring.

Flesh: Whitish to watery tan; sometimes insubstantial in stem.

Odor and Taste: Taste mild or bitter; odor sweet.

Chemical Reactions: KOH negative on cap surface.

Spore Print: White.

Microscopic Features: Spores 8-10 x 5-7 µ; smooth; more or less ellipsoid; inamyloid; with a prominent apiculus. Pileipellis a cutis of brown, frequently septate elements 7.5-15 µ wide, occasionally arranged in upright fascicles. Cheilocystidia clavate to subclavate or subsaccate; to about 40 x 10 µ; thin-walled; hyaline. Pleurocystidia absent. Basidia 2- and 4-sterigmate; not basally clamped.

REFERENCES: (Scopoli, 1772) Emel, 1921. (Saccardo, 1887; Kauffman, 1918; Smith, Smith & Weber, 1979; Weber & Smith, 1985; Arora, 1986; Berube & Dessureault, 1989; Phillips, 1991/2005; Lincoff, 1992; Metzler & Metzler, 1992; Horn, Kay & Abel, 1993; Volk, 2003; Miller & Miller, 2006; Kuo, 2007.) Herb Kuo 09190101, 07010306, 09300407, 08311301.

Armillariella tabescens is a synonym.

Further Online Information:

Armillaria tabescens at Tom Volk's Fungi
Armillaria tabescens at Roger's Mushrooms


Armillaria tabescens

Armillaria tabescens

Armillaria tabescens

Armillaria tabescens

Armillaria tabescens

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Kuo, M. (2013, September). Armillaria tabescens. Retrieved from the MushroomExpert.Com Web site: