Summary:
Features include minute, cup-shaped to convex fruitbodies that are whitish to pale yellowish, with a bright yellow interior, a stem that is two to three times as long as the cup is wide, gregarious growth on partly buried sticks and roots, and microscopic characters. Some authors including Dennis(1) give Hymenoscyphus calyculus (Sowerby ex Fr.) W. Phillips as the current name for this species. He says that Helotium virgultorum is an ill-defined name often used for the species. Hansen, L.(1) gives H. calyculus (Sowerby: Fr.) W. Phillips ss. auct. as a synonym for Hymenoscyphus virgultorum (Weber) W. Phillips. The online Species Fungorum, accessed March 1, 2018, gave the current name as Hymenoscyphus calyculus, but MycoBank gave the current name as Hymenoscyphus virgultorum.

Microscopic:
spores 15-20 x 4-5 microns, fusoid or subclavate [spindle-shaped or nearly club-shaped], partially biseriate, usually containing two oil droplets with several smaller ones, occasionally spuriously septate; asci 8-spored, reaching a length of 100-120 microns and a width of 9-10 microns, clavate; paraphyses filiform, slightly enlarged in upper part, (Seaver), spores 13-19 x 4-5 microns, elliptic to inequilateral, aseptate; asci 120-140 x 8-11 microns, (Hansen), spores 15-22 x 3-4.5 microns, cylindric, rounded in upper part and tapering in lower part, irregularly biseriate, sometimes appearing one-septate; asci 8-spored, up to 125 x 10 microns, cylindric-clavate, pore turns blue in iodine; paraphyses cylindric, up to 3 microns thick, (Dennis)

Notes:
Hymenoscyphus virgultorum is found from ON to CO, WA, CA, and Europe, (Seaver), and Denmark, Finland, Norway, and Sweden, (Hansen). There are two collections from BC at the Pacific Forestry Centre (as Hymenoscyphus calyculus but determined as Hymenoscyphus virgultorum by J. Groves). There are three collections from BC and one from OR at the University of British Columbia, all determined by O. Ceska.

Synonyms and Alternate Names:
Calvatia cyathiformis (Bosc) Morgan forma fragilis (Vittad.) Smith
Calvatia lilacina (Mont. & Berk.) Henn.
Helotium virgultorum (Vahl) Fr.
Phialea virgultorum Sacc.