70 A PLANT-DISEASE SUEVEY IN TEXAS. 



pycnidium contains brown spores, 15 by 6 /x, and three septate. It is 

 probably merely associated with a physiological languor, coming in 

 as a saprophyte. 



Specimen collected : Gonzales, 2698. 



Leaf -spot {Cercospora crataegi Heald and Wolf, 32). — This fungus 

 causes the formation of large, dark-brown, irregular areas from 5 to 

 10 mm. or more in diaifieter. The spots are darker above than be- 

 low, and when as many as 20 to 25 in number are confluent, involv- 

 ing large areas, with chlorotic tissue surrounding them. The upper 

 surface is broken by the numerous brown tufts of conidiophores and 

 conidia. The conidiophores are closely aggregated, 24 to 30 by 5 to 

 6 /A, brown and nonseptate. The conidia are clavate, straight or 

 curved, 120 to 180 by 5 to 7 fi, many septate with prominent guttulse. 

 (PI. lY, fig. 2.) 



Specimen collected: Gonzales, 2697 (type specimen). 



Rust {Gymnosporangium, glohosum Farl.).— The cluster cups of 

 this rust were found abundantly present on the leaves and twigs of 

 Crataegus crus-galli L. (See under '' Cedar.") 



Specimens collected: Austin, 1312. 1444 (cluster cups). 



Rust {Gymnos'porangiu'm sp.). — Several species of Crataegus have 

 been found whose leaves are covered by reddish-yellow areas, with a 

 group of black spermagonia at the center. 



Specimens collected: Elgin, 2009; Lockliart. 2069. 



HEMP TREE. 



Leaf-spot ( Cercospora mtieis Ell. and E v. ) . — Irregular, suborbicu- 

 lar, rusty spots, 2 to 4 mm. in diameter are formed on the hemp tree 

 (Vifex agnus-castus L.). The margin of the area is elevated and 

 darker, with a paler center as the sjDots become old. 



Specimen collected : Nursery, 2569, 



JAPANESE IVY. 



Leaf -spot {Phyllosticta lahruscae Thm,), — The spots produced on 

 the Japanese ivy {Psedera tricuspidata (Sieb. and Zucc.) Rehder) 

 by this fungus are subcircular, 5 to 8 mm. in diameter, reddish brown, 

 with a narrow dark border. The black pycnidia ojDen to the upper 

 surface. 



Specimen collected : Austin, 3103. 



LILAC. 



Leaf -blight {Cercospora macromaculans Heald and "Wolf, 32). — 

 Tliis blight on the lilac {SyAnga sp.) is characterized by the pres- 



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