190 THE FUNGI WHICH CAUSE PLANT DISEASE 



Spores with cross walls only 

 Spores elongate to oj'lindric 



Spores 4-celled, saprophytes 11. Perisporium. 



Spores 4 to 8-celled; parasites. ... 12. Schenckiella. 



Spores needle-formed 13. Hyaloderma. 



Spores muriform 



Spores brown 14. Cleistotheca. 



Spores hyaline 16- Saccardia. 



Aerial mycelium prominent 

 Spores with cross walls only 

 Spores hyaline 



Saprophytic 16. Scorias. 



Parasitic 17. Zvkaiin, p. 191. 



Spores brown 



Perithecia without apparent ap- 

 pendages 

 Perithecia rounded, opening 



irregularly 18. Antennaria, p. 192. 



Perithecia elongate, clavate, 



opening by regular slits. . 19. Apiosporium, p. 191. 

 Perithecia appearing to have 

 appendages 



Stromatic 20. Limacinia, p. 193. 



Not stromatic 21. Meliola, p. 193. 



(Some species of Meliola have muri- 

 form spores) 

 Spores muriform 

 Spores with an appendage at each 



end 22. Ceratocarpia. 



Spores not appendaged 



Subicle crustose 23. Capnodium, p. 192. 



Subicle radiate 24. Pleomeliola, p. 193. 



The genera of interest as pathogens induce disease rather by 

 covering, shading and smothering leaves with dense sooty-black 

 coatings than by parasitizing their hosts. They are not strictly 

 speaking parasites but live saprophytically upon the surfaces of 

 leaves, fruit and twigs often subsisting upon insects or insect 

 exudations, the so called "honey dew." 



