White, V.S. 1901. The Tylostomaceae of North America. Bulletin of the Torrey Botanical Club 28: 421-444.
Peridium depressed globose, 0.7-1 cm. high, 1-1. 5 cm. in diameter: outer peridium scaly, retreating and leaving a smooth whitish surface to the inner membranaceous peridium : mouth short tubular, entire, prominent: collar irregular, 3-5 mm. distant from the stem : stem equal, slightly thickened at the base, the outer coating lacerate scaly, whitish like the peridium, 4.-6 cm. long, 0.5 cm. in diameter : capillitium whitish, hyaline, branched, septate, slightly swollen at the joints, 4-6 p wide, free ends rounded : spores reddish brown, irregularly globose, pedicled, smooth, or if rough only a very few of them so, 4-5 µ in diameter. (Pl. 31, f. 4-7.)
Tulostoma albicans White (Fig. 4; Pls. III: 5-7;XXV: 6) Bull. Torrey bot Cl. 28: 428, pl. 31, figs. 4-7. 1901
= T. albicans var. nigrostium G.H.Cunningham, Proc. Linn. Soc. N.S.W. 50: 251. 1925.
Etym.: the name refers to the whitish colour of the endoperidium.
Spore-sac globose, up to 13 mm diam. According to Long (1947), apparently loosely adhered to the stipe. Exoperidium very thin, but obviosmembranous, when young dirty Sienna colour, later chalk-white. Long (op. cit.) described it as a sandy band, deciduous or almost, persistent as a band at the base. Endoperidium subsmooth, covered most of times with remains of the exoperidium as small squamules, later whitish. Mouth circular, small, slightly or not at all projecting. Socket very conspicuous, separated, shallow, with a thick membrane with a wavy or lacerate border. Gleba ochraceous. Stem up to 30 x 3.5 mm, rugose-squamose, cremeous to light wood-colour; scales appressed and sloughing off disorderly; ending basally in a small structure with volviform aspect.
Spores under L.M. almost smooth to minutely asperulate, globose to ellipsoid, some almost pyriform, guttulate, apiculate, some notoriously so, episporium thick, 4.8-6 Âµm diam; under SEM the ornamentation appears as short and anastomosed verrucae. Capillitium hyaline, branched and septate; threads thick-walled, with visible lumen to solid, 3-6.6 Âµm diam, slightly or not broadened at the transverse, coloured septa, disjointable.
Habitat: sandy soil.
Distribution: North America: United States (Arizona, California, New Mexico, Texas),Mexico. South America: Argentina (Chaco, Entre Rios, La Pampa, Mendoza). Europe: Spain, Sweden (?). Australasia: Australia.
Holotype: United States, Texas, leg. E.D. Cope, 1893 (NY!) (Cfr. Long, 1947).
Illustration: White (op.cit.), Lloyd (1906: pl. 77, figs. 5-6).
This is an ill-defined species, easy to mistake with others, mostly due to the indistinct ornamentation of the spores, even when observed under a high-power immersion oil objective. This results quite evident from the number of collections in the herbaria under this name that belong to other species. Our description coincides basically with Long's (1946), mainly in the measurements, but differs in the nature of the exoperidium. In a later paper, Long (1947) makes it a synonym of T. jourdani Pat., but I believe it ought to be maintained as valid until further evidence points to the contrary. Cunningham (1925) founded the variety nigrostium due to the dark colour of some peristomes, but later (Cunningham, 1942), he decided that the variety was not valid since this feature appeared in individuals of the same population.