Summary:
Tricholoma davisiae is easily recognized by 1) the dry, yellowish green cap and 2) the prominent acute umbo. The umbo is generally darker than the rest of the cap and dark green, fuscous green or fuscous, while the margin is yellowish green and finely scaly. (Ovrebo(2)). Other features include 3) fading of the cap to buff with the umbo remaining darker (A. Parker, pers. comm.), 4) sinuate gills that are yellowish green and buff and sometimes develop a pinkish tint, 5) a stem that is light greenish yellow and silky-fibrillose with a white base that is frequently tinged vinaceous when old, 6) flesh that is often tinged pinkish inside the stem base, 7) a farinaceous odor and taste, and 8) growth under pine. |It is frequent in the Pacific Northwest according to Smith(6). |The current name in the online Species Fungorum, accessed Nov 25, 2020, was Melanoleuca davisiae, but in MycoBank, accessed the same date, the current name was Tricholoma davisiae.

Cap:
4-11cm across, when young obtusely conic, expanding to broadly conic, convex-umbonate or flat-umbonate, the umbo distinctly acute, the margin often wavy and often slightly uplifted when old; fuscous, fuscous-green or dark green over umbo, the margin yellowish green, when old "lightening to light yellowish green, yellowish buff, grayish yellowish buff or grayish buff, rarely bleached buff overall when older", on drying buff overall, the fine scales colored as ground color or tinged brownish at tips, occasionally virgate [radially streaked] in places and then generally most evident on buttons; dry or rarely moist, densely interwoven-fibrillose over top of umbo, sides of umbo radially appressed-fibrillose, the margin with recurved fine scales, the fine scales generally beginning more or less halfway toward the edge from center, (Ovrebo(2)), 3-11cm across, broadly conic to convex becoming flat-convex, obtusely umbonate; dark brown over disc, yellowish to buff with tinge of pink toward margin; dry, tomentose over disc to innately fibrillose to fibrillose-scaly toward margin, (Smith), 3-11cm across, broadly conic to convex at first, becoming flat-convex or flat with obtuse umbo and upcurved, wavy margin; disc "cacao brown" or darker brown, margin yellowish or buff with a tinge of pink; dry, finely tomentose on the disc and innately fibrillose [virgate] toward margin, "fibrils sometimes breaking away and forming brownish fibrillose scales", occasionally the entire surface smooth, (Ovrebo(1)), Peck originally described young caps as bright yellow and often tinged with red or green (Bessette)

Flesh:
0.4-1.1cm thick, "light green when young, fading to greenish buff or buff when mature", in stem white but often tinged vinaceous in the base, (Ovrebo(2)), up to 1.6cm thick, often water soaked; whitish, occasionally with pinkish cast, in stem white in upper part and pink at base ("vinaceous buff"), (Ovrebo(1))

Gills:
"arcuate on buttons, sinuate when mature", close, subgills numerous but not arranged in distinct tiers, gills 0.4-1.5cm broad; light yellowish green or light green overall when young, when mature light yellowish green or light green at top and light buff on edge, the cap margin generally with most of the coloration, not discoloring or discoloring pinkish, occasionally light buff overall; edges entire, but occasionally splitting transversely, (Ovrebo(2)), sinuate, uncinate, subdistant; whitish then light buff or pinkish, yellowish near cap margin when old; edges even, (Smith), sinuate, uncinate, subdistant, 0.8-1.4cm broad, numerous tiers of subgills; whitish at first, becoming light buff, pinkish, ("pale pinkish buff", "pale ochraceous salmon"), and yellowing toward cap margin when old; edges even, (Ovrebo(1))

Stem:
5-14cm x 1-2cm, equal or rarely somewhat club-shaped, the base rounded, stem solid; "light greenish yellow overall or in large patches", generally fading when old, the basal area generally white but frequently tinged vinaceous when old; silky-fibrillose and with superficial fibrils projecting, occasionally finely scaly in places, often lightly furfuraceous at the top, (Ovrebo(2)), 5-15cm x 0.7-3cm, equal or wider in the middle or club-shaped; whitish to yellowish, pink at the base; dry, silky-fibrillose, (Smith), 5-15cm x 0.7-3cm, equal, ventricose, club-shaped; whitish to yellowish, distinctly pink at base; dry, smooth, silky-fibrillose, fibrils occasionally breaking away, (Ovrebo(1))

Odor:
farinaceous (Ovrebo(2), Ovrebo(1), Smith)

Taste:
farinaceous (Ovrebo(2), Ovrebo(1), Smith)

Microscopic spores:
spores (5.7)6.7-7.6(9.5) x 4.3-5.2 microns, elliptic, smooth, inamyloid, colorless, thin-walled; basidia 4-spored or rarely 2-spored, 29-38 x 7.6-8.6 microns, clavate, colorless; cheilocystidia 25-42 x 10.5-14 microns, "clavate, cylindric, or sphaeropedunculate, often multicellular, smooth, thin-walled, without content", colorless; clamp connections absent, (Ovrebo(2)), spores 6-7.5 x 3.8-4.5 microns, oblong to elliptic in face view, elliptic in side view, smooth, inamyloid, guttulate; basidia 33-39(45) microns long, clavate, smooth, inamyloid, contents homogeneous, or guttulate; pleurocystidia absent; cheilocystidia 26-33.8 x 12-22.5 microns, stoutly ampulliform, ventricose, or broadly clavate, contents homogeneous, colorless in KOH; clamp connections absent, (Ovrebo(1))

Spore deposit:
white (Ovrebo(2), Ovrebo(1))

Notes:
Material was examined from OR and ID, (Ovrebo(1)), and OR, ON, MA, ME, and MI, (Ovrebo(2)). Two collections from BC are at the University of British Columbia. Bessette(5) say it is widely distributed in northeastern North America (not mentioning the west) and show photographs from NY. Preliminary DNA research indicates the presence of T. davisiae in BC and WA, (D. Miller, pers. comm.).

EDIBILITY

Synonyms and Alternate Names:
Melanoleuca davisiae (Peck) Murrill (proposed current name)