DISEASES OF ORNAMENTAL PLANTS. 87 



appearance first on the distal portions of the leaves. The young spots 

 show a yellow center surrounded by a zone of watery tissue. The 

 older spots which have produced tufts of conidiophores are circular 

 or elliptical, reaching 3 to 8 mm. in length, and show a gray center 

 surrounded by a zone of brown, bordered by a narrow, watery area. 

 The fungus is much more abundant toward the tips of the leaves and 

 proceeds downward, the terminal portions of the leaves often becom- 

 ing brown and dead, with the more or less zonate spots still conspicu- 

 ous. In serious infections the leaf tissue turns yellow in advance of 

 the fungus, and many leaves may be completely killed. 

 Specimens collected : On Peace variety — Austin, 457, 1323, 1436. 



MAY-APPLE. 



Rust (Kuehneola hibisci (Syd.) Arth.). — This rust on the May- 

 apple (Malvaviscus drummondii T. and G.) produces very abundant, 

 almost punctiform sori upon the under surface of the leaves and 

 causes more or less browning of the upper surface. 



Specimen collected: Austin, 372. 



MEXICAN BLUEBELL. 



Leaf -mold (Cercospora nepheloides Ell. and Holw.). — Diffuse 

 olive-green patches appear on the leaves of the Mexican bluebell 

 (Eustoma russellianum (Hook.) Griesb.) At first these patches are 

 more or less circular, gradually spreading over large portions of the 

 leaf, with considerable chlorosis. In the advanced stages of the dis- 

 ease the conidiophores and conidia have become evenly distributed 

 over the brown, dead tissue. 



Conidiophores 30 to 42 by 3 to 4 /x, brown, in dense fascicles ; conidia 

 30 to 60 by 3 to 4 [x, brown, clavate, several septate. (PI. II, fig. 3.) 

 Both leaf surfaces are equally attacked, the lower leaves being most 

 affected. 



Our specimens agree with C. nepheloides Ell. and Holw. on E. 

 silenifolium Salisb. No published descriptions of this species have 

 been found, and the determination was made by a comparison of our 

 specimens with one issued by S. B. Parish under the above name, 

 labeled " Santa Barbara, Cal., Sep. '94." 



Specimen collected: Austin, 1556 (type specimen). 



PERIWINKLE. 



Dodder (Cuscuta indecora Choisy). — This parasite on periwinkle 

 (Vinca rosea L.) had run rampant in a garden. 

 Specimen collected: San Antonio, 1663. 

 226 



