76 A PLANT-DISEASE SURVEY IN TEXAS. 



leaflets, while the upper surface is somewhat paler. The minute 

 black pycnidia are very numerous on the under surface, but are 

 absent from the upper surface. It may be noted that the description 

 of Saccardo (47) gives the pycnidia as amphigenous. There is also 

 a considerable amount of yellowing of the leaf tissue adjacent to the 

 spots, and more or less defoliation results. 



Specimens collected : Austin, 238, 2908. 



Leaf -spot (Clasterosporiwn dijfusum Heald and Wolf, 32). — This 

 fungus produces circular or irregular, indefinite-margined, brown 

 spots, 5 to 10 mm. in diameter, which are uniformly brown on both 

 surfaces of the leaflets. 



The fungus produces dark-brown hyphse which run throughout the 

 dead tissue, or creep over either surface of the affected area, or are 

 sometimes aggregated to produce clusters of erect conidiophores. 

 Spores curved-clavate, many septate, brown, 45 to 135 by 4 to 5 /x. 

 (PL VII, fig. 4.) 



Specimens collected: Victoria, 2536; Gonzales, 2695 (type specimen); Yoa- 

 kum, 2770; Hallettsville, 2783. 



Scab (Fusicladium effusum Wint.). — This disease first produces 

 minute brown spots on the under surface of the leaflet which increase 

 in size until they reach 3 to 5 mm. in diameter. The spots are cir- 

 cular or subcircular, and in severe infections they may become con- 

 fluent. In the earlier stages the spots are confined to the lower sur- 

 face, but finally the leaf tissue is killed and the spot becomes dark 

 brown on the upper surface. It does not show the velvety appearance 

 of the under surface, since the conidiophores are entirely hypophyl- 

 lous. The scab spots occur also on the petioles. 



Specimens collected : Kerrville, 1570 ; Uvalde, 1927 ; Seguin, 2309. 



POISON OAK. 



Bust (Pileolaria toxicodendri (B. and Kav.) Arth.). — The small 

 chocolate-brown sori are formed in abundance on the upper surface 

 of the leaves of the poison oak (Rhus toxicodendron L.) . 



Specimen collected: Austin, 347. 



POMEGRANATE. 



Leaf-spot (Oercospora lythracearum Heald and Wolf, 32). — This 

 fungus on the pomegranate (Punica granatum L.) produces angu- 

 lar — more or less rounded — brown spots with an indefinite margin 

 below, 1 to 4 or 5 mm. in diameter, sometimes larger. Exceedingly 

 dense aggregates of conidiophores are present on both surfaces, 20 to 

 30 by 3 ju, clear or only faintly yellowish; conidia clavate, 30 to 56 

 by 3 to 3.5 /*, clear, septate. (PL I, fig. 5.) 



226 



