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Crepidotus malachius trichifer

by Michael Kuo, 25 April 2025

This variant of Crepidotus malachius is not easily distinguished from the typical variety—and neither mushroom is easily distinguished from Crepidotus applanatus. All are medium-sized to large Crepidotus taxa (also known as run-down elevators, since they are decrepit Otises) with brownish caps, round spores, and clamp connections. However, according to morphology-based research in the 1960s, Crepidotus malachius trichifer features a more yellowish cap and, under the microscope, several other features that distinguish it: its spores are slightly smaller than the typical variety, its cheilocystidia are long and flexuous, with apices that are rarely swollen but are sometimes branched; and it features pileocystidia, similar to the cheilocystidia. Contemporary, DNA-based studies have not yet thoroughly investigated this group in North America.

In Europe, the presence of Crepidotus malachius trichifer is debated; some collections given this label many years ago have been reevaluated as Crepidotus malachioides and/or Crepidotus ehrendorferi (see Ripková & Glejdura 2010, Jančovičová et al. 2014). The latter species is a decomposer of hardwoods and is remarkably similar to the collection described and illustrated here, featuring a yellowish cap and long, flexuous, occasionally branched cheilocystidia.

"Crepidotus malachius var. trichiferus" is a synonym.

Thanks to Regan Dixon for collecting, documenting, and preserving Crepidotus malachius trichifer for study; her collection is deposited in The Herbarium of Michael Kuo.

Description:

Ecology: Saprobic; growing gregariously on the deadwood of hardwoods and conifers; originally described from Mt. Rainier, in Washington (Hesler & Smith 1965), citing additional collections from the Pacific Northwest, as well as Michigan, New York, Tennessee, Mexico, and The Netherlands; distribution uncertain (see discussion above). The illustrated and described collection is from British Columbia.

Cap: 2–6 cm across; broadly convex; semicircular or fan-shaped; bald or very finely pubescent, especially toward the point of attachment; moist; pale brownish yellow; hygrophanous; the margin not lined at maturity, but occasionally slightly scalloped.

Gills: Close or nearly distant; radiating; short-gills frequent; when young whitish; becoming dull brown with maturity.

Stem: Absent.

Flesh: Whitish; unchanging when sliced.

Odor: Not distinctive.

Spore Print: Brown.

Microscopic Features: Spores 5–6.5 µm; subglobose; very finely stippled, or appearing nearly smooth; yellowish brown in KOH; inamyloid. Basidia 25 x 5 µm; subclavate; 4-sterigmate. Pleurocystidia not found. Cheilocystidia 40–90 x 4–7 µm; abundant; irregular: often cylindric-flexuous with rounded or subclavate to clavate apices, but also sometimes irregularly constricted or swollen, and occasionally with a small mucro; smooth; thin-walled; hyaline in KOH. Pileipellis a partially gelatinized cutis; elements 2.5–10 µm wide, smooth, hyaline in KOH; terminal cells often cystidioid and clavate, up to 40 µm long. Clamp connections present.

REFERENCES: L. R. Hesler & A. H. Smith, 1965. (Hesler & Smith, 1965; Senn-Irlet, 1995; Ripková & Glejdura, 2010; Jančovičová et al., 2014.) Herb. Kuo 10202401.

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Spore print

Spores

Cheilocystidia

Pileocystidia

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Cite this page as:

Kuo, M. (2025, April). Crepidotus malachius trichifer. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/crepidotus_malachius_trichifer.html