DISEASES OF WILD PLANTS. 93 



face of the leaves of the crane's-bill {Geranium carolinianum L.). 

 They may be small and isolated or may involve the entire surface. 

 In the earlier stages the upper surface of the foliage becomes 

 yellow, but finally the entire leaf becomes dead and dry. 

 Specimen collected : Austin, 2938. 



CROTON. 



Dodder {Cuscuta indecora Choisy). — This was very abundant on 

 the plants of croton {Croton spp.) in a single locality. 

 Specimen collected : San Antonio, 1373. 



Rust {Buhakia crotonls (Cke.) Arth.). — In this species of rust the 

 sori are very abundant. In the majority of specimens collected the 

 uredinia are more abundant than the telia. In some the telia are 

 much more abundant than the uredinia, and occur on both surfaces 

 of the leaves and on the petioles and stems. The telia on the leaves 

 are black, swollen cushions, still covered by the epidermis, 0.5 to 1 

 mm. in diameter and very abundant, causing the edges of the leaf 

 blade to roll upward and inward. The telia on the stems may be 

 similar in size to those on the leaf surfaces, but they are generally 

 much larger and may form elongated cushions 3 to 10 mm. in 

 length, which are confined to one side of the stem or completely 

 encircle it. ^\^len uredinia only are present the leaves may also be 

 curled and rolled, and the sori are frequently surrounded by a nar- 

 .row zone of yellow. Our collections represent various other species 

 of Croton in addition to C. texensis (Kl.) Muell. Arg. 



Specimens collected : Luling, 2258 ; Georgetown, 2380 ; Round Rock, 2418 ; 

 Falfurrias, 2442, 2489; Victoria, 2526: Cuero, 2582; Stockdale, 2647; Flatonia, 

 2736 ; Yoakum, 2757 ; Skidmore, 2817 ; Austin, 2907- All except 2907 represent 

 uredinia only. 



CROWNBEARD. 



leaf -spot {Cercospora fulvella Heald and Wolf, 32). — This disease 

 on the crownbeard {Verhesina texana Buckl.) is characterized by 

 the presence of irregidar, yellowish-brown areas, 5 to 10 mm. in 

 diameter, which sometimes become confluent, causing the death of 

 larger areas. The color is more dilute and the spots less definite on 

 the under surface. The conidiophores are epiphyllous or sometimes 

 amphigenous, fasciculate, brown, septate, 45 to 150 by 4 to 5 ju ; spores 

 clavate, straiglit, dilutedly colored, 40 to 60 by 4 to 5 fi, three to four 

 septate. (PI. Ill, fig. 7.) 



Specimen collected: Austin, 406 (type specimen). 



Leaf -spot {Phyllosticta verbesinae Heald and Wolf, 32). — This 

 fungus produces numerous gray or whitish subcircular spots, 1 to 3 

 mm. in diameter and surrounded by an indefinite darker zone which 



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