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Species Information
Summary: Onnia tomentosa grows on the ground near conifers or shelf-like on them, forming a yellow-brown to brown, soft, hairy or velvety cap that is circular to fan-shaped, with yellow brown flesh that has a soft upper layer and a firm lower layer, a pale to dark brown or grayish or hoary pore surface, a stem that is colored as the cap when present, and microscopic characters including abundant setae.
Onnia tomentosa has been found in BC, WA, OR, ID, AB, MB, NS, ON, PE, PQ, SK, AK, AL, AZ, CA, CO, DE, CT, IA, MA, MD, ME, MI, MN, MT, NC, NH, NJ, NM, NY, PA, TN, UT, VA, VT, WI, WV, and WY, (Gilbertson).
Cap: usually on the ground with a cap and short stem, but sometimes growing shelf-like on wood, 3-12(18)cm wide, circular to fan-shaped, convex to flat or centrally depressed; "whitish when very young but soon yellowish-brown to tan, dull ochre, brown, or rusty-brown, sometimes with faint concentric zones"; dry, soft and hairy or velvety, (Arora), up to 11cm wide, circular to fan-shaped, centrally depressed, sometimes lobed, "solitary or several branching from a common base", annual; upper surface yellowish brown, faintly concentrically zoned or not zoned; tomentose, (Gilbertson), "yellow-brown to darker brown, often with a pale edge when actively growing, and often zonate", (Trudell)
Flesh: "upper layer soft and spongy when fresh, lower layer rather thin, firm, and fibrous", yellow brown to brown, (Arora), up to 0.4cm thick, with a soft spongy upper layer and a firm fibrous lower layer; yellowish brown, (Gilbertson)
Pores: 2-4 per mm, round to angular or irregular becoming torn or sometimes tooth-like when old; "pale buff to grayish or beige or becoming brownish, but often with a hoary sheen or surface covering", darker brown where bruised; tubes 0.15-0.7cm long, usually decurrent, (Arora), 2-4 per mm, angular, with thick entire walls that become thin and torn when old; pale buff at first becoming darker brown when old; tube layer decurrent on stem, up to 0.3cm thick, white-stuffed and appearing lighter than the context, (Gilbertson)
Stem: when present 1-5cm long and 0.5-2cm thick, "central to off-center or lateral, continuous with cap and more or less the same color and texture, or darker", (Arora), up to 3.5cm long and 1.5cm wide, central or lateral or rudimentary, (Gilbertson)
Chemical Reactions: cap tissue blackening in KOH (sometimes with a fleeting red intermediate phase), (Arora)
Odor: pleasantly like curry (Breitenbach), fragrant (Miller)
Taste: mild (Breitenbach)
Microscopic: spores 4.5-7 x 2.5-4 microns, elliptic, smooth, colorless; brown setae abundant among basidia, straight and pointed, (Arora), spores 5-6 x 3-4 microns, elliptic, smooth, inamyloid, acyanophilous, colorless; basidia 2-4-spored, 13-15 x 5-6 microns, clavate; setae abundant, mostly 50-70 x 7-11 microns, but some up to 140 microns long, "mostly subulate, some ventricose, straight"; hyphal system monomitic: upper context hyphae 3-9 microns wide, pale yellowish to almost colorless in KOH, thin-walled, simple-septate, lower context hyphae 3-4 microns wide (thin-walled) or 5-8 microns wide (thick-walled), all pale yellowish, simple-septate, trama hyphae 3-6 microns wide, thin-walled, pale yellowish, simple-septate, (Gilbertson)
Spore Deposit: pale yellow to pale brown (Arora), whitish buff (Miller)
Habitat / Range
annual, single or in groups on ground under conifers, "(presumably arising from roots or buried wood), sometimes also on stumps or bases of trunks", (Arora), associated with conifers, particularly common with spruce, causes white pocket rot of the heartwood in roots and butt, distinguished by large empty pockets separated by apparently sound firm wood, (Gilbertson), sometimes enclosing plant remains (Breitenbach), fruiting in summer and fall (Miller)
Similar Species
Onnia leporina has larger thicker fruitbodies that grow on wood and mostly hooked setae microscopically (Gilbertson). O. triquetra (as O. leporina) typically grows under pine, with cap up to 18cm across, and the setae have hooked apices, whereas O. tomentosa typically grows under spruce, with cap up to 11cm across, and the setae have straight apices, (Ginns(28)). Pseudoinonotus dryadeus always grows shelf-like on wood, has a bald or nearly bald cap, has minute pores, and attains sizes of 30cm broad or more, (Arora). Phaeolus schweinitzii is usually larger and brighter in color, the fruiting body is compound, and the pore surface is mustard yellow to greenish when fresh rather than brown to grayish or hoary, (Arora). Coltricia species are not as thick and spongy (Arora). Coltricia perennis is distinctly zoned. See also SIMILAR section of Coltricia montagnei.
