52 A PLANT-DISEASE SURVEY IN TEXAS. 



gray or dirty-yellow center, bearing a central cluster of black acervuli. 

 The acervuli are on both surfaces and few in each spot. The spores 

 are falcate, acute pointed, hyaline, 20 to 27 by 4 to 5 /x, and frequently 

 show one to three large gi'anules. The conidiophores are short, 15 [x. 

 long, and nonseptate. The setse are pointed, with slightly bulbous 

 base, 1 to 2 septate, and reach 75 ix in length. (PL VI, fig. 15.) Our 

 specimens agree with C. Uneola Cda. in size of spores and setse and 

 with C. androfogonis Zimm.' in symptomatology. 



One field was observed where the disease was sufficiently developed 

 to cause the death of the grass. 



Specimens collected: Round Rock. 2410 (type specimen), 2427; Falfurrias, 

 2441, 2727 ; Yoakum, 2753 ; Floresville, 2844 ; Austin, 3036. 



Rust {Pucciiiia purpurea Cke.). — This rust occurs so abundantly 

 on the leaves that they are purple, the color being caused by the 

 closely clustered, elongated sori which rupture the epidermis on both 

 leaf surfaces. 



Specimen collected : Austin, 121. 



JUNGLE RICE. 



Gray-spot {Pirlcularia grisea (Cke.) Sacc). — Circular or oval yel- 

 lowish areas with purple margins appear on the blades of jungle rice 

 {Echinochloa colona (L.) Link). These spots are from 1 to 5 mm. 

 in diameter and become grayish below. The intervening tissues are 

 killed and the leaf tips become dry. (See under " Crab-grass.") 



Specimen collected: Uvalde, 1938. 



PANICUM. 



Black-blotch {Phyllachora graminis (P.) Fckl.). — The leaves of 

 Panicum {Pnnunim, spp.) become infested with black, shining, stro- 

 matic blotches. These are small, mostly less than 1 mm. in diameter, 

 and often confluent. The affected leaves become brown between these 

 spots. 



Specimens collected : Austin, 859 ; Elgin. 1895. 



Gray-spot {Pirieulana grisea (Cke.) Sacc). — Small elongated or 

 lenticular spots are formed. They are grayish brown Avith a brown 

 [)order, and are most abundant toward the tip of the leaf. Chlorosis 

 accompanies this spotting, and large parts of the leaves turn brown. 



Specimen collected: On Panicum texanum Buck. — Kennedy, 2834. 



» Dr. Zimmerman, to whom duplicates of our specimens were sent, reports tliat they are 

 identical witli C. andropoffonis Zimm. Edgerton, wlio is mailing a careful study of the 

 Colletotrichums. is of the opinion that C. Uneola Cda., C. andropogonis Zimm., C. cereaie 

 ilanns. and C. falcatum Went, may be identical. 

 226 



