THE FUNGI WHICH CAUSE PLANT DISEASE 89 



P. agaves Gan.'' occurs on the Agave in Mexico. 



P. nicotiana v. B. d H.™ is also closely related to P. omnivora, 

 but culture work shows it to be rather fastidious in its choice of 

 host as it attacks only tobacco seedUngs. 



P. calocasiae Rac. occurs on Calocasia antiquorum in the Orient. 

 An undescribed species on Castor is also reported.*' 



Eawakamia Miyabi (p. 83) 



Mycelium slender, copiously branched; conidiophores single or 

 in groups of 2-5 or more from the stomata, simple or sometimes 

 irregularly branched, but branches never arising near the conidia. 

 Conidia usually upon a slender pedicel cell, lemon-shaped, ob- 

 tusely tipped, contents and wall colorless, germination normally 

 by zoospores; zoospores oval, flattened and laterally biciUate; 

 oospores spherical, smooth. 



A single species, K. cyperi (M. & I.) Miyabe,*^ which was intro- 

 duced from Japan into Texas in imported plants of a sedge, 

 Cyperus tegetiformis. The species is very destructive in Japan. 

 Both conidia and oospores were produced in the Texan material.*^ 



Basidiophora Roze & Cornu (p. 83) 



B. entospora R. & C. occurs on species of Erigeron and culti- 

 vated aster in Europe and America. 



Sclerospora Schroter (p. 83) 



This genus differs from all other Peronosporales in the pre- 

 ponderance of its oospores; these are the conspicuous stage, while 

 the conidiophores and conidia are few, small and evanescent. 

 There are about five species. 



Mycelium much branched, with small vesicular haustoria; 

 conidiophores erect, solitary or in groups of two or three, 

 fugaceous, low and stocky, sparsely branched, the branches 

 also stocky; conidia elliptic or globose-elliptic, hyaline, smooth; 

 oospores globose, intramycelial, the epispore brown, irregularly 

 wrinkled, permanently vmited to the persistent wall of the oogo- 

 nium. 



