208 



ASCOMYCETES. 



will be found changing from vellow to black on account of 

 the periderm and dead stroma becoming darker. On dead 

 branches the large cushions of fructifications will be found to 

 include : {a) perithecia with a warty exterior and pores set 

 in a depression ; (&) large pycnidia, standing out from the 

 cushions, with brown smooth coats, and full of compound 

 multiseptate conidia (Fig. 9 9, B ; see below No. 3, a) ; (c) 

 other smaller pycnidia containing the same conidia, but whose 

 pore is situated on a sharp prominence (No. 3, V). All or any 

 of the three forms may be present. 



Fig. 99. — Cucurbitaria Idburni. A, Stroma with pycnidia containing minute 

 unicellular conidia. B, One of the large smooth pycnidia. (After v. Tubeuf.) 



The mature perithecia have a peridium consisting of a loose 

 pseudoparenchyma with a rough warty exterior and a pore set 

 in a distinct depression (Fig. 100.) The paraphyses are long, 

 strong threads, often branched, and between them arise the 

 long cylindrical asci with rounded ends. The normal number 

 of ascospores is eight in each ascus, but fewer is no exception. 



In addition to the forms already described, pycnidia of still 

 another sort occur (No. 1, c). They are spherical, with a 

 dark-coloured coarse peridium, and are smaller than the stroma- 

 pycnidia. These pycnidia contain no conidiophores, but give off 



