304 



COMPARATIVE MORPHOLOGY OF FUNGI 



1912, 1914; Theissen and Sydow, 1917; Hoehnel, 1917, 1918; Arnaud, 

 1918; Doidge, 1920). 



It is difficult to describe briefly the characters of the Microthyriaceae, 

 as all their forms merge into each other and into related families. In any 

 case, they are usually superficial ectoparasites. The ascus stromata are 

 provided with radial covers. In the Microthyrieae there is no aerial 

 mycelium at maturity; in the Asterineae, the mycelium is persistent, dark 

 colored, squarrose, asterinoid, often like the sooty moulds, aerial (Figs. 

 201 and 202). As in the Perisporiaceae, so also in the Asterineae, there 



Q^SapQ oooooQQQP 



Fig. 202. — Lembosia Bromeliacearum. 1. Section of fructification (X250). 2. Central 

 portion of mycelium bearing a fructification (X 34; after Arnaud, 1918.) 



are formed on the hyphae numerous specialized branches, hyphopodia 

 and stigmopodia. As there, so also here the stigmocysts may develop to 

 fructifications. Besides, the formation of fructifications may take place 

 directly under any hypha so that the hypha lightly touches the young 

 perithecium or it may — in the species without mycelia — take place directly 

 on the transitory germ mycelium which develops from the ascospores. 



In all these cases, the mother cells first divided to small cell complexes 

 which either remained discoid, flat and one layered or grew into knob-like 

 papillae, which frequently persisted a long time (Fig. 203, 1). This layer 

 grows centrifugally, so that the newly added cells have an elongate pris- 

 matic outline. Thus there is formed under the main hypha close to the 



