MONILIALES 



77 



8. Fertile hyphae short or only slightly distinct from the solitary conidia. 9. 

 Hyphae longer and distinct from conidia. II. 



9. Conidia smooth. lo. 

 Conidia with a slender appendage. Ceratophorum.* 



10. Conidia cylindric (more often saprophytic). Clasterosporium. 

 Conidia ovoid, in tufts. Stigmina. 



11. Conidia smooth, elongate or vermiform. 12. 

 Conidia echinulate, oblong. Heterosporium. 



12. Hyphae rigid (more commonly saprophytic). Helminthosporium. 

 Hyphae soft, simple or branched, often forming leaf-spots. 



Cercospora. 



13. Conidia soli taiy ; hyphae erect, somewhat fasciculate, soft. 



Macrosporium. 

 Conidia in chains ; hyphae velvety, erect. Alternakia. 



Conidia in chains ; hyphae crustaceous or interwoven. P'UMAGO. 



Of the above genera some are very numerous in nominal spe- 

 cies but it is more than probable that many of the described 

 species will prove identical after they have had more careful study 

 and cultivation. Cercospora is the largest genus of strictly leaf 

 parasites. Of over four hundred and fifty species, nearly half are 

 found in the United States, nearly every family of flowering plants 

 furnishing one or more hosts. The genus is specially abundant 

 in the Southern States (/Y, j./. 12). Besides Cercospora, Macro- 

 sporium has over eighty species, Cladosporiiiin has over a hundred, 

 and Helnimthosporiuin over a hundred and twenty-five. All these 

 three genera, however, are more commonly saprophytic and usually 

 appear as leaf fungi only after the death of the tissues. The 

 species of Funiago are doubtless related to Capiiodiuni, as the 

 ascosporic stage. 



Besides the genera which are regularly or occasionally parasitic 

 on leaves there are over one hundred others which are normally 

 saprophytic on dead wood and other substrata. Among the 

 forms with simple spores, Strcptothrix with short twisted hyphae 

 often forms numbers of brow^n rounded heaps on the bark of fallen 

 linden trees and sometimes those of other species. Glenospora 

 Ciirtisii is also common in the South, forming black patches on 

 living twigs and branches of Magnolia and other trees. 



^Cf. PI. s. f. 14- 



