Spore-sac large, up to 32 mm diam, easily separable from the stem. Exoperidium hyphal, forming a thick band of hyphae agglutinated with sand particles, persisting at the base as an acorn-cup. Endoperidium ochraceous whitish to ochraceous pinkish, papyraceous, tough, not totally smooth. Mouth formed by an elliptic aperture, plane. Socket very conspicuous and separated from the stem, up to 5 mm diam. Gleba cinnamon reddish. Stem concolorous with the endoperidium (wood-colour), longitudinally striatesquamose, sloughing off as in the stems of Battarraea, later becoming smooth, with a volviform formation at the base, slightly tapering downwards up to 110 x 8 mm or larger.

Endoperidium formed by hyaline, septate threads, septa hyaline, numerous, disjointable, and also by simple, parallel, much appressed hyphae Spores subglobose, 5.6-6.6 µm diam, generally with an eccentric guttula, episporium verrucose under L.M., some with small ribs or crests; under SEM the ornamentation appears finely verruculose. Capillitium hyaline to subhyaline, branched and septate; threads thick-walled, lumen hardly visible to lacunar, or completely solid, swollen at the scant, slightly oblique to transversal septa; 3-6.7 µm diam. Habitat: in sandy soil of dunes, partially shaded by Prosopis.

Distribution: North America: SW United States.

Holotype: United States, New Mexico, 10 mi W of Deming, on Hway 70, leg. Long & Stouffer, 12.IX.1941 (Herb. Long n° 9369, BPI!).

Illustration: Long (op. cit., fig. 2).