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 5". Sorghi. 



II. Spores purplish, verruculose 5". 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/x 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/x in length. The spores are purplish, 

 broadly oblong or ovate to (chiefly) subspherical, very mi- 

 nutely but abundantly verruculose and 10-17^ in length. 



Hosts and Distr.: Polygonum acre, Green's Farms, Sept. 



