218 



COMPARATIVE MORPHOLOGY OF FUNGI 



At maturity the papillae break off and the conceptacle parenchyma, 

 possibly still present over the asci, is dissolved so that the tips of the asci 

 are free. As Meliola and Parodinopsis of the Perisporiaceae, so also 

 Botryosphaeria of the Dothioraceae has perithecia whose place of opening 

 is typical. They do not, however, open by pores but by histologically 

 differentiated parts of the stroma which, because of the formation of 

 dehiscence zones, are more easily crumbled away. 



B. Ribis causes the currant cane blight (Grossenbacher and Duggar, 

 1911; Shear, Stevens and Wilcox, 1925). In July the first conidial forms 

 (in the imperfect genus Macrophoma) appear on the withering young 

 shoots; in the following spring there break forth from the dead branch 



Fig. 142. — Parodiellina manaosensis. Section through lower surface of leaf with concep- 

 tacle and setaceous conidial stroma. (X 110; Arnaud, 1921.) 



numerous black stromata which first bear the pycnidia of the second 

 imperfect form, Dothiorella, and later swell with the perithecia. 



This type of the highest species of Botryosphaeria appears again 

 in the Dothioraceae with many modifications. In Parodiellina manaos- 

 ensis on the under side of leaves of Brazilian Solanaceae, two stromata 

 break out, one of which cuts off dark brown, uni- or multicellular con- 

 idia, while the other bears perithecioid conceptacles (Fig. 142). The 

 stroma surrounding these conceptacles consists of solid cells and is an 

 intense reddish brown. When young, it is entirely closed, but at 

 maturity gradually crumbles at the top. The ascigerous stromatal parts 

 seem extraordinarily like the fertile branches of Myriangium, especially 

 if one imagines the basal stroma in Fig. 137 less well developed, as is 

 actually the case in many species, except they are more individualized 

 with consequent reduction in number of asci. 



