22 CONNECTICUT GEOL. AND NAT. HIST. survEY. [Bull 
the spore mass as the latter wears away. See Fig. 37. This 
genus has not been thoroughly worked up for the whole world, 
and so a number of the species belonging under it are now in- 
cluded under Ustilago. Only two of the 16 species occurring 
in North America are of economic importance. So far only 
two species have been found in Connecticut. 
Key to Species of Sphacelotheca. 
I, Spores olive brown, smooth............+++.. S. Sorghi. 
II. Spores purplish, verruculose.......... S. Hydropiperis. : 
Sphacelotheca Sorghi (Lk.) Clint. Figs. 5, 24, 26, 38. 
The sori occur in the ovaries, forming oblong or ovate bodies 
usually 3-8 mm. in length, or rarely fusing the aborted spike- 
lets into longer forms. The brownish false membrane wears 
away from the apex, revealing the olive brown spore mass and 
finally the evident slender columella. The sterile cells of the 
membrane easily break up into groups, and are hyaline, oblong 
to subspherical, and chiefly 7-18 in length. The olive brown. 
spores are subspherical or spherical, smooth, often have pitted 
contents, and are 5.5-8.5 in diameter. 
Hosts and Distr.: Sorghum vulgare var. sorghum, New 
Haven, Sept. 30, 1903; Sorghum vulgare var. technicum, New 
Haven, Sept. 20, 1901 (Rorer), Sept. 11, 1903. 
This species was found on both sorghum and broom-corn 
grown at the Experiment Station. So far as I can learn, 
neither of these plants is grown commercially in the state, so 
the smut is of no economic importance here, though further 
west it often does considerable injury to these plants. 
Sphacelotheca Hydropiperis (Schum.) DeBy. Figs. 6, 
37. The sori are found in the ovaries, forming oblong or 
ovate bodies 3-5 mm. in length; with the false membrane de- 
hiscing at the apex, and revealing the purple-black spore mass 
and finally the slender columella. The sterile cells, besides 
forming the false membrane, constitute part of the columella; 
they easily separate, are hyaline or slightly violet tinted, chiefly 
subspherical, and 6-17 in length. The spores are purplish, 
Broadly oblong or ovate to (chiefly) subspherical, very mi- 
nutely but abundantly verruculose and 10-1 7» in length. 
Hosts and Distr.: Polygonum acre, Green’s Farms, Sept. 
