Summary:
{See also Morels Table.} Morchella tomentosa is distinguished from other morels by the densely tomentose and often black surfaces when young. Features are densely tomentose young ridges that are black to gray or brownish, the ridges eroded or flattened when old, bald pits that vertically elongate by maturity, young stem that is densely tomentose and gray to black, and fruiting at 1000-3400 meters altitude in years following forest fires. Older specimens "may have eroded ridges and paler colors that approximate the colors of M. esculenta-like yellow morels" [Latin name italicized] but these still demonstrate pigmented hairs on ridges and stem surface and can thus be distinguished microscopically (Kuo). The description is derived from Kuo(3) except where noted.

Microscopic:
spores (15)18-20(22.5) x (7.5)8-12.5(15) microns, elliptic, smooth, contents homogeneous; asci 8-spored, 225-290 x 12.5-20 microns, cylindric, colorless; paraphyses (125)150-175(225) x 5-10(15) microns, cylindric to subclavate, apices rounded to subacute, 2-5 septa, colorless or with brown to brownish homogeneous contents in 2% KOH, residual paraphyses on sterile ridges similar, bundled, colorless or with brown contents; hairs on sterile ridges projecting from residual paraphyses, abundant, 120-250(400) x 7.5-15(25) microns, "variable in shape (cylindric, clavate, subclavate, lageniform, or subcapitate)", with brown to brownish contents in 2% KOH, septate, often with thickened walls; hairs on stem surface abundant, 100-275 x 10-17 microns, cylindric to subclavate, with brown walls in 2% KOH, septate, contents colorless to brownish

Notes:
Morchella tomentosa has been found in OR, ID, YT, AK, CO, and MT, (Kuo(3)). Collections of "Morchella atrotomentosa nom. prov." from BC at the Pacific Forestry Centre are likely to represent this species.

Synonyms and Alternate Names:
Polyporus mollis Pers.
Tyromyces mollis (Fr.) Kotl. & Pouzar