FUNGOID PESTS OF CULTIVATED PLANTS. 239 



GRASS CULM SMUT. 

 Ustilago hypodytes (Fr.), PI. XXII. fig. 22. 



This very common smut attacks the culms and sheaths of a great 

 number of grasses, being developed within the sheaths, and extending up 

 the culms in a black powdery crust, chiefly on coarse grasses. 



The spores are globose or ellipsoid, sometimes irregular or angular 

 (3-6 x 8-4 /u), with a smooth surface, blackish in the mass, but indivi- 

 dually of an olive-brown colour. 



Known in Britain, France, Germany, Belgium, Netherlands, Hungary, 

 Italy, Northern Africa, and North America. 



Sacc. Syll vii. 1641 ; Cooke, M. F. p. 229, figs. 100-101 ; Cooke, Hdbk. 

 No. 1524 ; Plowr. Brit. Urecl p. 278. 



Another smut attacks the leaves of Glyceria aquatica and -fluitans, 

 forming long parallel streaks (Ustilago longissima) of a greyish-olive 

 colour. But these cannot be considered as cultivated grasses. 



GRASS BUNT. 

 Tilletia striiformis (West.), PL XXIII. fig. 23. 



This appears to be the same species as was described by Berkeley under 

 the name of Ustilago Salvcii, and it occurs on the leaves, sheaths, and 

 culms of various grasses, such as Anthoxanthum, Holcus, Festuca, Poa, 

 Agrostis, and Lolium. 



The pustules are dark brown, disposed in long lines ; at first covered, 

 and then exposed and powdery, spores spherical or elliptical, sometimes 

 rather irregular, but rarely oblong (10-13-17 x 8-12ju), the exterior 

 spinulose, connected in a network at the base, olive-brown. Germinating 

 and producing secondary spores after the same type as in Wheat Bunt. 



Known also in France, Belgium, Germany, Finland, Austria, Italy, and 

 North America. 



Often found on Cock's-foot (Dactylis glomerata), from which it is liable 

 to spread to pasture grasses. 



Sacc. Syll. vii. 1774 ; Cooke, M. F. p. 230, figs. 117-119 ; Cooke, Hdbk. 

 No. 1528 ; Plowr. Brit. Ured. p. 284. 



POA GRASS RUST. 

 Uromyces Poa (Rabh.), PL XXIII. fig. 30. 



This is another of the fertile progeny of the species of cluster-cups 

 found on Buttercups, which are said to be responsible for several rusts, 

 parasitic on grasses. The present species is found on several species of 

 Poa. 



The pustules of the uredo are rounded, elliptical, or linear, at first 

 covered, then splitting longitudinally, orange. Uredospores rounded or 

 elliptical, finely echinulate (16-26^u diam.), orange-yellow. 



