384 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
ordinarily included under Ustilago. The genus differs from Ustilago 
by the possession of a definite false membrane composed chiefly of 
stei He fungous cells , and there are, no doubt, a number of species 
that have been described under Ustilago that more properly belong 
heie. On the other hand, some of the Ustilagos often show remains 
of the gelatinized fungous threads in the enveloping tissues sur¬ 
rounding the sorus. The central columella of Sphacelotheca is usu¬ 
ally composed almost entirely of the hard plant tissues, though in 
the type species this is also composed of sterile fungous cells. In 
many of the species, especially where the columella is represented 
by several strands of plant tissues, masses of these sterile cells are 
also found scattered through the sorus. Sorosporium, also, is often 
provided with a similar false membrane , but in this genus the spores 
aie united in balls, at least when young. The presence of a central 
columella generally induces a centripetal development of the spore 
mass, and so some of the species of Sphacelotheca, and Ustilago 
also, have been improperly placed by some botanists under Cin- 
tractia. The species occur chiefly on the Gramineae and sixteen 
have been listed here. Sorokin’s genus, Endothlaspis, is based on 
a covering membrane of sterile cells, as shown by his figures and 
description, and so evidently belongs here. 
* Spores brownish. 
Sphacelotheca pamparum (Speg.) Clint. 
Ustilago Setariae Niessl ?, Speg., Fung. Argent., pug. 2, no. 24. 1880. 
Ustilago pamparum Speg., Fung. Guar., pug. 1: 49. 1886. 
Ustilago Kolaczekii Iviilin, Rab.-Wint., Fungi Eur., 3401. 1886. 
Sphacelotheca pamparum Clint., Journ. Myc., 8: 140. 1902. 
Exsiccati: Ustilago pamparum Speg., on Setaria sp., Syd., Ust., 162. 
Sori infecting all of the ovaries of the spike, extending between 
the glumes as oblong bodies about 3—7 mm. in length, with evident 
false membrane which ruptures irregularly from apex into several 
elongated lobes and discloses a somewhat dusty, olive black spore 
mass and an evident columella; cells of false membrane chiefly hya¬ 
line, oblong to subspherical, adhering together rather permanently, 
chiefly smaller than the spores; spores reddish brown, ovoid to 
spherical but chiefly polyhedral through pressure, minutely verrucu- 
l°se, 9—12 /x, rarely 14 g, in length. 
