THE FUNGI WHICH CAUSE PLANT DISEASE 227 



Spores hyaline, sometimes be- 

 coming brown 16. Melanopsamma. 



Spores hyaline to green 17. Thaxteria. 



Spores dark-colored 18. Sorothelia. 



Spores 3 to many-celled 



Spores hyaline 19. Zignoella. 



Spores dark-colored 20. Melanomma. 



Spores elongate, spindle-form, hya- 

 line, many-celled 21. Bombardiastrum. 



Coleroa Fries (p. 226) 

 Perithecia free, small, globose, flask-shaped; asci 8-spored; spores 



r\H\ \ \ XT' 



fw-- 



Fig. 161. — C. ehaetomium. C, perithecia; D, asci. 

 After Lindau and Winter. 



ovate, 2-celled, hyaline, green or golden-brown; paraphyses poorly 

 developed. 



Conidia= Exosporium. 



This genus, of some thirteen species all of which are parasitic, 

 is quite similar to Venturia. The chief economic species are C. 

 ehaetomium (Kze.) Rab. (Conidia= Exosporium rubinus) on Rubus 

 in Europe and C. sacchari v. B. d H., on sugar cane in Java.^^^ 



