SPHAERIALES 



259 



There are three genera in the Chaetomieae, Chaetomidium, Ascotricha 

 and Chaetomium; the first is distinguished by the lack of an ostiole and 

 thus shows its relationship to the saprophytic Perisporiaceae ; the second 

 by a neck with ostiole crowned by a tuft of hairs; the last includes those 

 with ostiole without tuft of hairs and neck (Bainier, 1909; drivers, 1915). 

 They occur chiefly on dung and decaying plants. Their imperfect forms 

 are very manifold; thus in Chaetomium Boulangeri are formed Graphium 

 coremia with a dark brown to black stipe up to 20 n thick which 



Fig. 173. — Ascotricha chartarum. 1. Perithecium with setae about the ostiole. 2. 

 Conidiophore of Dicyma form. 3. Branch of conidiophore. 4. Conidiophore of Sporotri- 

 chum form. (1 X 105; 2 X 60; 3, 4 X 980; after Boulanger, 1897.) 



disappears above in a broom-like, lighter-colored and finally hyaline 

 fertile part (Lindfors, 1920). In Ascotricha chartarum (C. Zopfii) on the 

 rind of Piscidia erythrina (Boulanger, 1897), two imperfect forms have 

 been discovered, one a Sporotrichum type with smooth, hyaline conidia 

 (Fig. 173, 4) and a Dicyma type with echinulate, ovoid, thick-walled, 

 dark brown gemmae (Fig. 173, 3). These, on dark-colored, sympodially 

 branched conidiophores (Fig. 173, 2), appear deceptively like the sterile 

 bristles on the neck of the perithecium. In other Chaetomieae, other 

 conidial forms have been noted (thus Verticillium, etc.). 



