THE DEUTEROMYCETES (FUNGI IMPERFECTI) 385 



port of both these apparently contradictory statements is of- 

 fered by the imperfect form Genus Gloeosporium. Some species 

 of the pyrenomvcetous genera Glomerella and Gnomonia have 

 conidial stages belonging to Gloeosporium. The conidial stage of 

 certain species of the discomycetous Pseudopeziza has also been 

 regarded as Gloeosporium. Again, Marssonia (Marssonina) 

 jiigland'is is the conidial stage of Gnovionia leptostyla, a pyreno- 

 mycete, A\'hereas Marssonia rosae and M. fragariae a*re conidial 

 stages of Diplocarpon rosae and D. earliana, respectively, both of 

 ^^•hich are discomycetous. But life-history studies have revealed 

 that the correlated parallelism between form of conidia and form 

 of ascospores is a very useful feature in classification. Species of 

 Guicrnardia, for example, have Phyllostictina as their conidial 

 stage, species of Rhytisma have Alelasmia, species of Cordvceps 

 have Isaria, species of Gibberella have Fusarium, species of Pleo- 

 spora have Alternaria or Macrosporium, species of Elsinoe have 

 Sphaceloma, species of \^enturia have Fusicladium, species of 

 Coccomyces (Higginsia) have Cylindrosporium, and species of 

 Sclerotinia {sensji lato) have Alonilia and Botrytis. Parallelism in 

 form of conidia and ascospores, however, may not exist, as is 

 shown by species of Diaporthe that possess conidial stages belong- 

 ino^ to Phomopsis and by species of Alycosphaerella that have co- 

 nidial stages among a variety of genera, including Phyllosticta, 

 Ascochyta, Ramularia, Cercospora, Cercosporella, and Septoria, 

 and by species of Nectria whose- conidial stages are classified as 

 Tubercularia, Fusarium, or Cyhndrocarpon. Some genera, such 

 as Balansia, Epichloe, and Dothichloe, on the other hand, possess 

 conidial stages belonging to one and the same form genus. In 

 these genera the conidial stages are included in Ephelis. 



The conidial stage and the perfect or ascigerous stage are rarely 

 found in nature at the same season. Many species, especially 

 those attacking annual host plants or the foliage and fruit of 

 deciduous trees and shrubs, produce their ascigerous stage in the 

 spring. It is apparent, therefore, that the perfect stage is less 

 conspicuous than the conidial stage and hence is less frequently 

 collected. These facts may account for the widely prevalent 

 but erroneous opinion that the ascigerous stage of such fungi is 

 of infrequent or rare occurrence. 



By means of pure-culture techniques it has been possible to 

 secure evidence of o-enetic connection between the conidial stajje 



