238 



COMPARATIVE MORPHOLOGY OF FUNGI 



etc. Hypomyces ochraceus on Russula has hyaline conidia, called Verti- 

 cillium agaricinum, its ochraceous gemmae being Mycogone puccinioides. 

 H. chrysospermus lives mainly on Boletus; its golden-yellow gemmae were 

 called Sepedonium chrysospermum. The imperfect Mycogone rosea, 

 which also may belong to Hypomyces, along with others lays waste the 

 mushroom cellars. Hypomyces species, whose conidia are of the Thie- 

 lavia type, are placed in Pyxidiophora. As far as the cytological develop- 

 ment is known for Hypomyces, it follows the Melanospora type. In H. 

 rosellus (Dangeard, 1907) and H. aurantius (Vincens, 1917), the hyphal 

 cells are multinucleate, in H. ochraceus (Dangeard, 1907) uninucleate. 



The representative of the second stage in which the perithecia are 

 united on or in undifferentiated stromata, as Sphaerostilbe in the Didymo- 



Fig. 153. — Hypocrea delicatula. Habit. (Natural size; after Tulasne.) 



sporeae, Stilbonectria in the Phragmosporae, and Megalonectria in the 

 Dictyosporae, arise directly from the stromatic forms of the first stage and 

 frequently may not be easily distinguished from them. Their conidio- 

 phores, in contrast to the stromatic Nectriaceae, are joined into clavate 

 coremia at whose base the perithecia develop. In the Brazilian Megalo- 

 nectria verrucosa, the ascospores germinate to a sprout mycelium in the 

 interior of the ascus, as in some Nectriaceae. Sphaerostilbe repens causes 

 a root disease of Hevea in Ceylon. 



In the representatives of the third stage, the stromata gradually 

 develop to definitely formed fructifications; they have been studied in five 

 genera: Hypocrea, Corallomyces, Mycocitrus, Peloronectria and Shiraia. 

 The species of Hypocrea are distinguished in that their bicellular asco- 

 spores at maturity separate into single cells, so that the asci apparently 



