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 jamesiana (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 (Helminthosporium turcicum 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 /x, guttulate, and are 

 extruded so abundantly as to make a white coating. (PL VI, fig. 17.) 



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



Leaf -spot {Oercospora 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 (Colletotrichum 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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