SPHA EROPSIDA LES 7 1 



it will be possible to demonstrate the presence of asci in those 

 species in which they are normally produced so that one need not 

 ordinarily be in doubt as to the true position of the plant under 

 examination. 



The striking similarity of certain of the Sphaoropsidaceae to the 

 Sphaeriales leads one to suspect that in some cases the former 

 are really members of the Sphaeriales in which the ascus has be- 

 come abortive. In a number of species, however, the true asco- 

 sporic condition is known in addition to the pycnidial stage, and 

 probably a similar relation exists between many species of Sphae- 

 ropsidaccae on the one hand, with described Sphaeriales on the 

 other. The discovery of such relations is no simple matter, and 

 with our present knowledge of methods of cultivation, the certain 

 demonstration of relationship is often impossible. 



The Zythiaceae* with light colored pycnidia bear the same 

 relation to the Hypocreales, that the last family does to the 

 Sphaeriales. The species of the fourteen genera are mainly 

 saprophytic. The genera are mostly small, Zythia, the largest 

 having ten species, only two of which are reported from this 

 country with a third from Cuba. 



The Leptostromataceae with shield-shaped pycnidia, while 

 not distinctively leaf-parasites, include numerous species among 

 the thirteen genera that inhabit the living or languid leaves of 

 some of the higher plants The genera containing such leaf- 

 parasites may be distinguished as follows : 



1. Spores one-celled, hyaline, globose or ellipsoid. 2. 

 Spores 2-many- celled, hyaline, fusiform. DlSCOSiA. 

 Spores 4-celled, the cells arranged in the form of an irregular cross. 



Entomosporium. 



2. Walls of the pycnidia distinctly parenchymatous. 3. 

 Walls of the pycnidia not parenchymatous. Sacidium. 



3. Pycnidia splitting longitudinally, somewhat hysterioid. 4. 

 Pycnidia without a mouth, never splitting longitudinally. 5. 



4. Pycnidia lanceolate or elongate. Leptostroma. 

 Pycnidia nearly circular. Labrella. 



* This family has commonly been known as Nectrioideae, but as this 

 name is not derived from that of a representative genus of the family, and 

 further does not have the regular family ending, we make the above substi- 

 tution. 



