216 COMPARATIVE MORPHOLOGY OF FUNGI 



Plectascales, but elongate-clavate ; they are pressed together in a palisade 

 and force the stromatic ground tissue, the so-called interthecial stroma 

 (Fig. 139, 2) together to paraphysoid filaments, the pseudoparaphyses or 

 paraphysoids (terminology of Petrak, 1923). The paraphysoids differ 

 from paraphyses in that, as the remains of the interthecial stroma, they 

 have a cellular structure and do not terminate freely but continue further 

 into the pseudoparenchymatous cover tissue. 



In the higher Dothioraceae, as in Bagnisiopsis, there appears, as in the 

 Myriangiaceae, a tendency to limit the asci to definite, narrowly limited 

 conceptacles which are differentiated out of the interior of the stroma 

 (Fig. 140). The dull black, pulvinate stroma of the Brazilian Bagnisiop- 

 sis peribebuyensis is erumpent from the leaves of various Melastomataceae 

 dotting their surface with small papillae. In contrast to Bagnisiella, 

 the asci do not form a continuous layer but are localized in sharply 

 defined nests which, like the fertile parts of Myriangium, are generally 

 surrounded by a darker tissue. They lie singly (as in Bagnisiella and the 

 other Myriangiales) in special loculi and are separated from each other 



Fig. 140. — Bagnisiopsis peribebuyensis. Section of mature stroma with two ascigerous 



conceptacles. (X 33; Arnaud, 1921.) 



by thin stromatal layers. With this spatial limitation of the asci, the 

 whole stromatal cover does not degenerate at maturity but small parts, 

 which have lain directly over the conceptacles, crumble and form an 

 irregular pore through which the ascospores escape (Fig. 140, left). 



During further development of the Dothioraceous line the single 

 conceptacle is gradually individualized. Like the fertile branches of 

 Myriangium, they sprout from the sterile stroma, thereby acquiring 

 their own wall while sterile stroma becomes more and more limited to 

 the intramatrical part. 



This development may be followed in Botryosphaeria (Theissen and 

 Sydow, 1915; Theissen, 1916; Hoehnel, 1920). The simpler species, 

 as B. inflata (Fig. 141, 1) appear entirely like Bag?iiopsis but occupy a 

 partly lower stage, for their conceptacles are scattered irregularly over 

 the stroma and are still entirely imbedded in the plectenchyma; at 

 maturity their tips project only a little beyond the stroma and hence 

 hardly raise the bark of the host. In other species, as B. Viburni (Fig. 

 141, 2 and 3), they gradually collect and arch toward the surface of the 

 stroma; but still, according to the luxuriance of the stromata, they may 

 be surrounded by the plectenchyma entirely or only to half their height. 



