268 BOTANICAL GAZETTE [NOVEMBER 
loosely interwoven hyphae, which are obviously mycelial elements 
elevated to their present position chiefly by the upward growth of 
a central knot of conspicuous, deeply staining threads. The latter 
are of peculiar interest on account of the part they play in the 
development of the fertile system. At first sight, because of their 
marked differentiation from the other threads composing the young 
fructification, they might easily be taken for ascogenous hyphae, 
or even for ascogonia. At a later stage (fig. 6) the proliferations of 
these threads give rise to bodies of characteristic form and history, 
bodies that admit of one interpretation only, namely, that they are 
procarps. The first appearing threads must therefore have some 
significance other than this. 
Clearly differentiated bodies are known to originate the procarps 
or corresponding bodies in various Ascomycetes. In Ascobolus 
carbonarius (DopGE 8) the procarps arise through the germination 
of asexual conidia borne on special mycelial branches. BRowN (3) 
found that in X ylaria tentaculata the Woronin hyphae are formed 
by the continued modification of threads that are differentiated at 
the center of the perithecium anlage while the latter is very young 
and deeply imbedded in the stroma. According to Miss DAwsoN 
(6), a well differentiated thread appears in Poronia punctata, which 
at a later stage grows into a procarp. 
The nearest approach to the first differentiated hyphae of 
Cudonia is to be found, however, in the disco-lichens. NIENBURG 
(18) gives a description of the development of the fruit bodies of 
four of these lichens, Usnea barbata, Baeomyces roseus, Sphyridium 
byssoides, and Icmadophila aeruginosa. It appears from his account 
that more or less well developed carpogonia arise in these forms, 
not from the ordinary hyphae of the ascomata in which they are 
found, but from threads which are differentiated at a considerably 
earlier stage. To these threads NreNBuURG applied the name 
“Primordialhyphen” or “generativen Hyphen.” In Icmadophila 
they appear before the fruit body has begun to rise above the 
surface of the thallus. 
NIENBURG apparently was not very logical in his use of the terms 
““Primordialhyphen”. and “generativen Hyphen.” He employed 
the first in his study of Usnea, and the latter in studies of Bae- 
