342 BOTANICAL GAZETTE [april 



supposed, but are the precursors of coiling procarps which arise 

 from them at a later stage, in a manner to be described. 



So far as the writer is aware, such a sequence of structures has 

 not elsewhere been reported for any species of the Ascomycetes 

 proper. Among the lichens, however, a similar condition has 

 been recorded. In a paper dealing with the ontogeny of the 

 ascocarp of several forms of lichens, Nienburg 4 figures and de- 

 scribes bodies which are differentiated early in the process of 

 development, and which at a later stage give rise to "carpogones." 

 These bodies are designated "generativen hyphen" by this author. 

 Following his usage, the term "generative hyphae" will be employed 

 in reference to the threads here described and to their immediate 

 proliferations. 



developmental 



of vegetative tissues. 



rganized 



covering, which completely envelops the looser tissues, and at the 

 center the generative hyphae are more conspicuous than ever. 

 By this time the generative hyphae have proliferated to a slight 



more 



with 



As growth 



proceeds the outer tissue expands, remaining in its peripheral 

 position as a true veil. Its persistence and growth are not functions 

 solely of the tissues that lie beneath it, but of itself as well. By 

 its own growth it is able to keep pace for a considerable time with 

 the rapid enlargement of the cap, a fact that is true even of that 

 portion which is eventually separated from its connections by the 

 developing hymenium. This growth, in contrast with mere 

 stretching, results in a marked increase in the thickness of the 

 veil, measurements showing that the earliest envelopes average 

 about 20 /i, while at maturity they approach 70 /x in thickness. The 

 veil ruptures over the hymenium only, and there only after the 

 latter is well matured. 

 By upward growth 

 may be termed parenchymatous 



mass 



fruit, the generative hyphae are forced to assume a subapical 



* Nienburg, W., Beitrage zur Entwickelungsgeschichte einiger Flechtenapothe- 

 cien. Flora 98: 1907-1908. 



