284 INTRODUCTION TO THE STUDY OF FUNGI 



Dematieae, for Trichosporium fuscum is found forming the 

 subiculum of Rosdlinia aquila, and the common Bispora 

 monilioides is reputed to constitute the conidia of a small 

 Peziza, hence called Bisporella Tnonilifera ; but this appears to 

 us a doubtful case. Fusicladium depression is reported to be 

 the conidia of Phyllachora angelicae, and Polythrincium 

 trifolii of Phyllachora trifolii. Species of Gladosporium, 

 of Cladotrichum, and Helminthosporium respectively are be- 

 lieved to be related genetically to various species of the 1 

 Sphaeriacei, and especially species of Macrosporium to certain 

 species of Pleospora. It is sufficient for our purpose to suggest 

 these relationships as indicating the evidence on which the 

 Hyphomycetes are concluded to be imperfect Fungi, and 

 principally conidial forms of Ascomycetes. 



After this digression we may return to the two inferior 



families of the order, in which 

 the hyphae are fused into a com- 

 mon stem. The Stilbeae (Fig. 

 131) are of a more imposing 

 appearance than the Tubercu- 

 larieae, and perhaps of a higher 

 sCt^ WPfW development. There are not 



' , „, „ ,„ * more than about five hundred 



Fig. 131. — Stilbum vulc/are. 



described species, and these are 

 grouped in two parallel sections : the Hyalostilbeae, in which the 

 hyphae and conidia are pallid ;. and the Phaeostilbeae, in which 

 the hyphae and conidia are typically dusky coloured Thus 

 these two sections correspond to the Mucedineae and the 

 Demafieae. 



The Hyalostilbeae, as far as at present known, are less 

 variable in fructification than the Phaeostilbeae, it being found 

 necessary to recognise but two of the subsections : the 

 Amerosporae, in which the conidia are globose or oblong, 

 and continuous ; and the Phragmosporae, in which the conidia 

 are septate. The latter is a very small section, of some seven 

 or eight species, so that practically the Hyalostilbeae. have small 

 and continuous spores, or conidia. The subsidiary arrangement 

 is very much on the same lines as in the moulds. The 

 principal genera are the old ones of Stilbum and Isaria, with 



