92 A PLANT-DISEASE SURVEY IN TEXAS, 



row darker border. The number of infections on a single leaf may 

 reach as high as 400 to 600, in which case the leaf shows more or less 

 chlorosis, but frequently the spots are less numerous and the leaf 

 shows little or no deviation from the normal color. 



Conidiophores amphigenous, fascicles of 3 to 8, hyaline tipped, 

 irregular-nodose for two-thirds the length, continuous or rarely 

 septate, 3 to 3.5 by 60 to 100 p. Spores 105 to 135 by 3 ^ and reaching 

 the length of 245 /i in some cases, very slender club shaped, tapering 

 gradually from the base, generally somewhat curved, hyaline, and 

 obscurely septate except in the basal portion. (PI. II, fig. 4.) 



Specimens collected: Lining, 2236; Georgetown, 2383 (type specimen) ; Nur- 

 sery, 2567; Cuero, 25S8 ; Gonzales, 2705; Yoakum. 2755; Hallettsville, 2790; 

 Kennedy, 2S36; Austin, 2871. 



Rust {Puccinia want hi S.). — The rust of the cocklebur is very com- 

 mon, producing numerous circular or slightly irregular spots on the 

 leaves (minute to 1 cm. in diameter), pale yellow and sunken on the 

 upper surface, dark brown with narrow yellow border on the under 

 surface, and somewhat hypertrophied. Old spots frequently show 

 gray centers on the under surface. 



Specimens collected : Austin, 1413, 1545 ; Beeville, 1800 ; Lockhart, 2065 ; San 

 Marcos, 20S8 ; Hondo, 2251; Luling, 2241; Seguin, 2302; Georgetown, 2381; 

 Victoria, 2343 ; Gonzales, 2664 ; Kennedy, 2822 ; FloresviUe, 2849. 



CONVOLVULUS. 



White-rust {Albugo ipomoeae-panduranae (S.) Swingle). — The 

 white, blisterlike spots on the convolvulus ( Convolvulus hermanioides 

 Gray) were present on all parts of the plant. This disease is not 

 recorded (51) as occurring on this species. 



Specimens collected : Austin, 311, 814. 1265. 



CORAL BEAD. 



Leaf -spot (Cercospoixi menispermi Ell. and Holw.). — On the foliage 

 of this climbing vine {Cebatha Carolina (L.) Britton) very abundant 

 dark-brown spots are present, 2 to 5 mm. in diameter. The margin of 

 the spot pales out from a raised border which is almost black. With 

 age the centers of the diseased areas become grayish. The spores are 

 generally clavate, sometimes cylindrical, from 30 to 60 by 5 to 6 /*, 

 brown, three to five septate. 



No defoliation results. 



Specimens collected : Sabinal, 1987 ; Bastrop, 2036 ; San Marcos, 2089 ; Luling, 

 2230 ; Seguin, 2313 ; Round Rock, 2409 ; Gonzales, 2681 ; FloresviUe, 2846. 



Downy mildew (Rhysotheca geranii (Pk.) Wilson). — Very con- 

 spicuous, definite, downy, white areas are formed on the lower sur- 



226* 



