354 



FUNGI 



layer of protoplasm coating the wall. At this stage the full growth of 

 the ascus is commonly reached, and the formation of ascospores begins 

 with the division of the nucleus into two ; then by the same process 

 four appear, then eight, which in the majority of cases represents the 

 number of ascospores. In many Ascomycetes, however, other numbers 

 typically prevail, e.g. one, or two, or four, or sixteen, forty, fifty, and so 

 on to over a hundred. Dothidea (Fr.), for example, has two to four, Sor- 

 daria (Ces. and De Not.) four, sixteen, sixty-four, and one hundred and 

 twenty-eight. Whatever the number, the nuclei always possess the same 



Fig. 300. — Peziza {Pyronetnd) conflue-ns P. a, small portion of hjjmenium ; p, paraphyse attached" 

 to, not originating in, hyphal branches from which the three asci spring ; 7«, young asci ; ? — 70, 

 successive stages, according to letters, in the development of ascospores within asci ( x 390). (After 

 de Bar>'.) 



structure in all stages of multiplication, but they become smaller in 

 size as the number advances. Round each nucleus there gathers a clear 

 mass of protoplasm, and ultimately this becomes enclosed by a mem- 

 brane, aiid, growing in size, thus develops into a spore. The ascospores 

 are arranged in a series, one over the other within the ascus. The 

 protoplasm left over within the ascus and outside the sporej differs from 

 that within the spores in exhibiting a reddish or violet- brown colour 

 after treatment with iodine solution. De Bary originally proposed the 

 -term ' epiplasm ' for this portion of the contents ; but, Errera having. 



