DISEASES OF WILD AND CULTIVATED GRASSES. 53 



REED-GRASS. 



Leaf-spot (Hendersonia arundinacea (Desm.) Sacc). — This fungus 

 produces brown, elongated spots on the leaves of reed-grass (Phrag- 

 mites vulgaris (Lam.) B. S. P.). The spots are 1 to 2 cm. in length, 

 most commonly confluent, causing the drying of the leaves. The 

 upper surfaces of the affected areas at maturity become grayish with 

 a brown margin. 



Specimen collected: San Marcos, 2109. 



SAXD BUR. 



Smut (Sorosporium syntherismae (Pk.) Farl.). — This smut de- 

 stroys the complete inflorescence of the sand bur (Cenchrus sp.). 



Specimen collected : Skidmore. 2807. 



SILVER BEARD-GRASS. 



Black-blotch (Phyllachora graminis (P.) Fckl.). — This parasite on 

 silver beard-grass (Andropogon argyraeus Schult.) produces on the 

 leaves black, shining blotches. The spots are small, oblong, prom- 

 inent, sometimes confluent, with a rugulose surface. The fructifica- 

 tion is not mature until the leaves are dead and decaying. 



Specimens collected: Austin, 297, 356. 



Smut (Tolyposporella orunki (Ell. and Gall.) Clint,).— The leaf 

 sheaths inclose a black, powdery mass of spores, which has taken the 

 place of the inflorescence. 



Specimen collected: Austin, 1727. 



SORGHUM. 



Bacterial blight (Bacillus sorghi Burr.). — This trouble is very gen- 

 erally present on all the varieties of sorghum (Andropogon sorghum 

 (L.) Brot.) grown in this section, such as milo maize, Kafir corn, and 

 cane. It produces on the leaves elongated purplish or dark-brown 

 patches quite commonly confluent, so that large portions of the leaf 

 are discolored. Many of the specimens represent mixed infections 

 of Colletotrichum spots and bacterial blight. 



Specimens collected: Boerne, 1653; New Braunfels, 1691, 1701; Sabinal, 1968; 

 Hondo, 1993 ; Bastrop, 2020 ; Lockhart, 2067 ; Cotulla, 2161, 2203 ; Seguin, 2298 ; 

 Stockdale, 2612; Flatonia, 2723; Floresville, 2848. 



Head-smut (Sphacelotheca reiliana (Kuhn.) Clint.). — The head- 

 smut is not uncommon on the various varieties of sorghum, but is not 

 so generally abundant as the kernel smut. 



Specimens collected: San Antonio, 1794; Uvalde, 1926; Bastrop, 2051; San 

 Marcos, 2104; Seguin, 2292; Victoria, 2350; Stockdale, 2636; Gonzales, 2701; 

 Hallettsville, 2799. 

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