Peck C.H. 1895. Bulletin of the Torrey Botanical Club 22: 209.
Peridium subglobose, usually a little longer than broad, 6 to 8 lines broad, 9 lines long, glabrous above, ferruginous-tomentose on the lower half; ostiolum entire, stem equal, about 2 in. long, even and glabrous or but slightly furfuraceous on the upper part, the lower part longitudinally sulcate, whitish; spores ferruginous, globose, .00016 to .0002 in. broad; threads of the capillitium colorless, not septate.
Sandy soil. Nevada. Collected by C. W. Irish; communicated by T. Taylor.
This species is separated from T. mammosum Fr. by its peridium, which is tomentose on the lower half and not depressed, and by its stem, which is distinctly furrowed in its lower half.
Etym.: The name probably refers to thesulcate nature of the stem.
Spore-sac subglobose, generally higher than wide, up to 20 mm diam; firmly attached to the stem. Exoperidium thinly membranous, persisting only in small patches, especially at the base and around the mouth, covered by sand in the lower portion. Endoperidium coloured, subsmooth, yellowish brown to dirty ochraceous, lighter towards the base, appearing mottled, parchment-like. Mouth circular to elliptic, large, almost 4 mm diam., applanate. Socket deep and wide, well separated from the stem. Gleba dark dirty ochraceous to ferrugineous. Stem almost white, longitudinally substriate, up to 50 x 5.5 mm, straight, without evidence of a volva but it may have been present, woody, glabrous except the upper third where it is furfuraceous.
Spores yellowish brown to light brown, globose to elliptic, minutely verrucose under L.M., 5.1-6.4 Âµm diam, or 4.6-5.4 x 4.3-5 Âµm; under SEM the ornamentation appears as small, much appressed and even, blunt verrucae. Capillitium hyaline, branched, septate; threads thick-walled, lumen visible to solid, disjointable at the non swollen, scant, brown, transverse septa; 2.5-7.6 Âµm diam.
Habitat: sandy soil in arid regions.
Distribution: North America: SW United States.
Holotype: United States, Arizona (Not Nevada, as was published by WHITE 1901), leg. Irish, comm Taylor (NYS!).