252 Dawson.—On the Biology 
some under natural conditions and others in pure cultures, 
in captivity. The distribution, described above, of these 
swollen hyphae seems to indicate that they may possibly have 
some important connexion with the formation of perithecia, 
and they may indeed be genetically connected with the 
hyphae from which these arise. Moreover it is not impossible 
that at even this early stage in the development of perithecia 
some fusion of the contents of two different hyphae may have 
taken place ; but it must be acknowledged that, in spite of 
a careful search over a large number of preparations, no proof 
of such a union could be found, although, as Fig. 18^ shows, 
the nucleus in the swollen apical cell of the hyphae is of an 
unusually large size. 
These hyphae present a striking resemblance to the deeply 
stained hyphae figured by Marshall Ward 1 in Stereum hir- 
sutum , and also to the very young ascogenous hyphae described 
by Krabbe 2 in Cladonia stellata , though in this latter case 
they are related to one ascus only and not to a whole 
apothecium. 
Similar early stages in the formation of ascogenous hyphae 
have been figured by Dittrich 3 in Mitrula phalloides. There 
is also the possibility that these clavate hyphae are members 
of a system of conducting tissue such as that described by 
Istvanffi 4 5 in some species of Stereum and Radulum . 
If sections of a slightly older stroma than that shown in 
Fig. 17 be examined, it will be seen that from the outermost 
layers of hyphae numerous conidia have been formed, giving 
rise to a thick covering of spores over the top and sides 
of the swollen portion of the head. This reminds us of the 
behaviour of the stromata of the closely related Xylaria b , 
and indeed of many other Ascomycetes, Nectria , Claviceps , &c., 
which always produce crops of superficial conidia before the 
1 Marshall Ward, Phil. Trans., vol. clxxxix, 1897. 
2 Krabbe; cf. Von Tavel, Vergleichende Morphologie der Pilze, 1892, Fig. 31. 
3 Dittrich, Cohn’s Beitrage, viii, 1898, Figs. 1, 5, 7. 
4 Istvanffi, Bot. Centralbl., 1887; Prings. Jahrb., 1896. 
5 Cf. De Bary, Comp. Morph. Fungi, p. 244. 
