DISEASES OF WILD PLANTS. 105 



spots show as lighter areas in a dark ground. In the earlier stages 

 of the disease a considerable degree of chlorosis may be exhibited. 

 Specimens collected : Austin, 64, 2870. 



WILD GOURD. 



Leaf -spot {Cercospora cucurUtae Ell. and E v.). —Dirty-yellow, sub- 

 circular or angular spots, 2 to 7 mm. in diameter, are produced on 

 the wild gourd {Cucurhita foetidissima H. B. K.) by this fungus. 

 The spores are 57 to 173 /i in length. This range of size is different 

 from that given in the original description (48) (100 to 120 /x). 



Specimens collected : New Braunfels, 1717 ; Llauo, 1754 ; Elgin, 1877 ; Loclihart, 

 2086; Austin. 359, 1923; Sabinal, 1984; Luling, 2269; Seguiu, 2289; Floresville, 

 2845; San Antonio, 3161. 



WILD TOBACCO. 



Leaf-spot {Cercospora nicotianae Ell. and Ev.).— This fungus on 

 the leaves of wild tobacco {Nicotiana repanda Willd.) forms sub- 

 circular areas 5 to 10 mm. in diameter. Because of the production 

 of conidiophores and conidia on both surfaces, the center of the 

 affected areas is brown with a lighter border. 



Specimen collected: Austin, 3034. 



WIND FLOWER. 



Rust {Tranzschelia cohaesa (Long) Arth.).— The densely aggre- 

 gated cluster cups, yellowish or dilutedly brown, appear on the lower 

 surface of the foliage of the wind flower {Anemone caroliniana 

 Walt.) . The margins of the cups show quite commonly four recurved 

 rays. This rust is very common and very abundant during March. 



Specimens collected: Austin, 2935, 2944. 



Smut {Urocystis anemones (P.) Wint.). — The brownish -black 

 pustules are formed on the stems, petioles, and leaf blades. These 

 pustules are covered at first and vary in size from very small to 2.5 

 or 5 cm. in length when on the stems. 



Specimen collected: Austin, 2942. 



WOOD SORREL. 



Smut {Ustilago oxalidis Ell. and Tracy). — The seeds of the wood 

 sorrel (Oxalis stricta L.) are replaced by a mass of brown spores, and 

 when the capsule dehisces these spores are forcibly ejected in clouds. 



Specimens collected: Austin, 1261, 1263. 

 226 



