220 INTRODUCTION TO THE STUDY OF FUNGI 



to be almost analogous to that of Asterina in the Perisporiaceae. 

 In this genus the perithecium is flat and membranaceous. 

 Amongst the subgenera, Myiocopron has continuous sporidia; in 

 the typical subgenus they are uniseptate, and in Seynesia the 

 uniseptate sporidia are brown. In the genus Clypeolum the 

 perithecia are carbonaceous, and shield-like, with uniseptate 

 hyaline sporidia ; or in the subgenus Vizella continuous and 

 brown. In the subgenus Scutellum they are septate and coloured. 

 The two remaining genera are Micropenis and Pemphidium ; in 

 the former the perithecia are convex and the sporidia multi- 

 septate and hyaline ; in the latter the perithecia are scutate, 

 the nucleus gelatinous, and the fusiform sporidia brown. 



Polymorphism of a somewhat elaborate form has been 

 credited to some of the Pyrenomyceteae. Take, for instance, 

 the very common Pleospora herbarum, on dead stems. That 

 ubiquitous black mould, Cladosporium herbarum, has been 

 recorded as one conidial form. This also has been suspected 

 of merging into Macrosporium commune, which again has been 

 named as a form of conidia of the same Pleospora. By a 

 further development the Macrosporium, in some occult manner, 

 appears with the spores in chains, and then again, under the 

 name of Alternaria tenuis, is referred to the Pleospora ; so that 

 three supposed species of Dematieae have been recorded as 

 conidia of Pleospora herbarum. Then again one of the 

 Sphaeropsideae, having perithecia, but with stylosporous fruit 

 and named Phoma herbarum, has been called the spermogonia 

 of the same Pleospora. At the same time it may be asked 

 what function is ascribed to these spermogonia ; for if, as 

 M. Cornu has suggested, they are capable of germination, then 

 the small sporules are not spermatia, or fecundating bodies, as 

 the name would imply, but have some other function. What 

 again are the bodies termed pycnidia ? Until the process has 

 been traced, for at present it is little more than suspected, 

 accurate phraseology cannot be applied. Conidia, of various 

 forms, and for the most part of the nature of Hyphomyceteae, 

 are common enough, and possibly produce a mycelium upon 

 which perithecia are afterwards developed, but so much is at 

 present only a matter of faith, which remains for the future to 

 demonstrate. 



