Tricholoma scalpturatum
yellowing knight
Tricholomataceae

Species account author: Ian Gibson.
Extracted from Matchmaker: Mushrooms of the Pacific Northwest.

Introduction to the Macrofungi

Photograph

© Adolf Ceska     (Photo ID #18620)


Map

E-Flora BC Static Map

Distribution of Tricholoma scalpturatum
Click here to view the full interactive map and legend

Species Information

Summary:
Features include 1) a dry cap that is gray brown felty at the center and scaly toward the paler margin, 2) white gills that become yellow spotted, 3) a dry stem that is white to minutely gray brown fibrillose, and 4) farinaceous odor and taste. Tricholoma scalpturatum (Fr.) Quel. sensu lato includes T. argyraceum (Bull.) Kummer, T. inocybeoides A. Pearson, and T. myomyces var. alboconicum J.E. Lange, according to Hansen, but the description is also given from Moser who also recognized T. argyraceum and T. inocybeoides: Tricholoma argyraceum was described approximately as follows by Moser(1): CAP 4-8cm across, light gray, hairy, floccose then scaly-silky, GILLS white then yellow-spotted, STEM 4-8cm x 0.6-1.2cm, white, ODOR barely perceptible, HABITAT pine woods, MICROSCOPIC spores 7-9 x 4-5 microns, NOTE white form has cap creamy to dingy white with fine brown to gray fibrils. Tricholoma inocybeoides was described by Moser(1) approximately as follows: CAP 1-4cm across, conic then domed with sharp umbos, pale gray, later whitish, finely fibrous, GILLS whitish, sometimes yellowing, STEM 2-3cm x 0.4-0.5cm, white, sometimes reddish or yellowish spotted, ODOR unpleasant, HABITAT deciduous woods. Ovrebo(2) separates T. argyraceum by its lighter cap and lack of farinaceous odor, and notes (Ovrebo(5)) "The concept for T. scalpturatum has consistently included the yellow discoloration to the lamellae while the concept for T. argyraceum has not." (Latin names italicized).
Cap:
3-6cm across, conic to bell-shaped to acutely umbonate, "finally with reflexed and fissile margin"; gray brown felty at center and scaly toward paler margin, (Hansen), 4-8cm across, shield-shaped-flat, gray, gray brown, fibrous or fine scaly, (Moser), margin yellows when older (Bacon)
Flesh:
thin; white, discoloring yellow, (Hansen)
Gills:
white, becoming yellow spotted, (Hansen), yellowing when old, often also when damaged, (Moser)
Stem:
3-7cm x 0.5-1cm, white to minutely gray brown fibrillose, sometimes with traces of cortina, (Hansen), 3-8cm x 0.7-1cm, white fibrous, (Moser)
Veil:
cortina gray, "disappearing, but sometimes almost ring-like", (Moser)
Odor:
farinaceous (Hansen), weakly floury (Moser)
Taste:
farinaceous (Hansen)
Microscopic spores:
spores narrow, 2.5-3.5 microns, (Hansen), spores 5-6(7) x 3-4 microns, (Moser), [presumably smooth, inamyloid]
Spore deposit:
[presumably white]
Notes:
Ovrebo described collections for T. scalpturatum from MI, MN, and ON. According to Shanks(2) T. scalpturatum is found in CA. There are O. Ceska collections of T. scalpturatum from BC at the University of British Columbia and two collections from WA at the University of Washington. It has been reported from ID by Cripps. Bessette(5) say it is widely distributed across northern N. America and show photos from AZ and QC.
EDIBILITY

Habitat and Range

SIMILAR SPECIES
In contrast to Tricholoma myomyces, Tricholoma scalpturatum tends to be paler, with scattered dark fibrils over a pale background, and has gills that discolor yellow, (Shanks). In contrast to T. myomyces, T. scalpturatum tends to be paler, has farinaceous odor and taste, has gills and stem that discolor yellow, and lacks a pseudoparenchymatous hypodermium, (Ovrebo(2)). T. myomyces "lacks the yellow staining and has a darker colored cap, pseudoparenchymatous hypodermium, and longer broader spores", (Bessette(5)). Tricholoma terreum differs by the same features as T. myomyces but additionally lacks a cortina, (Bessette(5)). Tricholoma moseri "is smaller, lacks a cortina, has flesh with either farinaceous or non-distinctive taste, and occurs primarily in spring or early summer in the mountains of western North America", (Bessette(5)). Tricholoma triste is in general smaller, lacks the farinaceous odor, and has a scaly stem, (Ovrebo(2)).
Habitat
single, scattered, or in groups under conifers or hardwoods: "Currently, the dominant concept in Europe is of a hardwood species that occurs only occasionally with conifers. This is the opposite of the prevailing concept in North America", (Bessette(5) who separate T. cingulatum, T. argyraceum, T. inocybeoides, and T. alboconicum), gregarious to subfasciculate [somewhat bundled] with hardwoods, bushes, scrub, from late summer, (Hansen), grassy woods (Moser), summer, fall, (Bacon)