MYRIANGIALES 



217 



In B. mascarensis (Fig. 141, 4) they develop entirely above the surface 

 of the stroma upon which they rest at maturity; hence these are true, 

 sterile, basal stromata, as in Bagnisiopsis peribebuyensis. Along with 

 this development, there has been a fundamental alteration in the course 

 of the stromatal hyphae. While in the lower forms, as in B. inflata, 

 they still run entirely irregularly, in the higher forms they have become 

 increasingly vertical and finally run parallel from the base to the top of 

 the stroma. 



In the highest stage, as in B. Bakeriana, B. Quercuum and B. Ribis, 

 the stromata begin to buckle and split between the conceptacles which are 

 left standing on shorter or longer stipes and have their own walls, i.e., 

 they become perithecia. 



1 



Fig. 141. — Development of stroma in Botryosphaeria. 1. B. inflata. 2, 3. B. Viburni. 

 4. B. mascarensis. 5. B. Bakeriana. (After Theissen, 1916.) 



B. Quercuum (Melanops Quercuum) forms its brown stromata on oak 

 bark between the periderm and the bark parenchyma beneath and pushes 

 out the periderm which it ruptures with radial splits, so that the perider- 

 mal lobes remain like steep walls. Meanwhile it has grown higher, but 

 seldom to such a degree that it projects over the peridermal lobes. As in 

 Myriangium, there develop columnar outgrowths which broaden spheri- 

 cally above and end at the top with a conical papilla. This conceptacle 

 tissue is, as in the other Dothioraceae, entirely like the basal stroma in 

 structure and is continuous with it. The spherical head portion is also a 

 pseudoparenchymatous mass. In it, a hyaline spherical conceptacle, 

 containing a palisade of monascous loculi, is differentiated. The para- 

 physoids are occasionally not only pressed together into threads but also 

 dissolved so that the asci are embedded in a gel. In this condition, the 

 conceptacle appears entirely like the true perithecium and only its onto- 

 geny shows its Myriangial character. 



