DISEASES OF WILD AND CULTIVATED GRASSES. 51 



Smut {Ustilago hypodytes (Schl.) Fr.). — The internodes of the 

 inflorescence beginning at their bases are enveloped for the greater 

 part of their length by a dusty, dark-brown spore mass, and the spike- 

 lets are destroyed. 



Specimens collected: Austin, 2950, 3098. 



GRAMA GRASS. 



Rust {Puccinia janiesiana (Pk.) Arth.). — This rust on grama 

 grass {Bouteloua sp.) was observed in a single locality, where it was 

 not abundant. 



Specimen collected: Falfurrias, 2481. 



JOHNSON GRASS. 



Leaf -blight {Helmtntliosforium, tureicum Pass.). — The diseased 



areas on Johnson grass {Andropogon, halepensis (L.) Brot.) are 



dark purple, often almost black, from 5 to 10 mm. in diameter, 



and are elongated parallel to the veins. They are frequently flattened 



on the side of the veins and show a pronounced zonation. These spots 



become confluent, resulting in the death of the leaf tips. 



Specimens collected : Bastrop, 2024 ; Luling, 2232 ; Elgin, 2010 ; San Antonio, 

 1409; Sabinal, 1983; Austin, 3036. (The last three are mixed infections, Colle- 

 totrichum being present.) 



Leaf -blight {Septoria pertusa Heald and Wolf, 32). — The diseased 

 areas are elongated parallel to the veins and are 1 to 2 cm. in length 

 without a definite margin. The brownish center is surrounded by a 

 yellow zone which pales out into the green. These areas become con- 

 fluent so that whole leaves are dry and yellowish brown in color. The 

 flask-shaped pycnidia are very abundant on both surfaces and protrude 

 by a short papilla. (PI. VI, fig. 16.) The conidia are clear, straight, 

 or slightly curved, slightly clavate, 60 to 75 by 3 fi, guttulate, and are 

 extruded so abundantly as to make a wdiite coating. (PI. VI, fig. 17.) 



Specimens collected; Luling, 2270; Flatonia, 2722 (type specimen). 



Leaf -spot {Cercospora sorghi Ell. and Ev.). — No definitely limited 



spots are produced by this fungus. The affected areas are reddish 



purple with a tinge of red along the border. The production of conid- 



iophores and conidia renders the center of these areas somewhat 



brown. 



Specimens collected : Flatonia, 2741 ; Hallettsville, 2800; Gonzales, 2668. (Im- 

 mature specimens, Colletotrichum being also present.) 



Leaf -spot {Colletotrickum lineola Cda. var. halepense nov. var.). — 

 This fungus on the leaf blades produces circular or slightly elongated 

 spots which have an average length of about 2 mm., but may reach 5 

 mm. or more in length. The spots have a bright-red border with a 



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