168 BOTANICAL GAZETTE [MARCH 
meanwhile have continued their growth, dividing in such a manner 
as to produce a larger number of chains of cells which arrange 
themselves spirally about the central coil and form what is to 
become the wall of the perithecium. 
This coiled structure is the ascogonium or ‘‘Woronin’s hypha,” 
described by various workers in a considerable number of Ascomy- 
cetes. I do not consider the hypha connecting it with the stroma 
above in any way analogous to a trichogyne, however, but rather 
as being similar to and corresponding to the hypha described by 
Miss Dawson (14) as leading from the stroma beneath and giving 
rise to ‘‘Woronin’s hypha” in Poronia punctata. The apparent 
differences between the two cases are that in Poronia the peri- 
thecium is formed in the upper part of the stroma, and the hypha 
which gives rise to the ascogonial coil comes up from below and 
does not leave the stroma; while in Guomonia ulmea the peri- 
thecium is formed beneath the stroma in the tissue of the host, 
which renders it necessary for the thread which is to give rise to 
the ascogonium to leave the stroma and grow downward into the 
leaf tissue. In each case the hypha enters the perithecial primor- 
dium at a point which is finally located in the basal portion of the 
mature perithecium. In Poronia, however, after coiling to form 
the ascogonium, it continues to grow on beyond the perithecium 
to the outer surface of the stroma as a somewhat narrower thread, 
which reminds one of the trichogyne of Collema, as described by 
BACHMAN (3), of Physcia by DARBISHIRE (11), and of Polystigma 
by Frank (18) and Fiscu (17), but not by BLACKMAN and WELLs- 
FORD (4). This “‘trichogyne”’ was not present in Guomonia ulmea. 
Brooks (6), in working with Gnomonia erythrostroma (Auers.) 
Kleb., found an ascogonium similar to the one described for 
G. ulmea, and also certain structures which he called trichogynes. 
He was able to trace a connection between these hyphae and the 
peripheral layers of the young perithecium only, never with the 
ascogonium itself. These peripheral layers would correspond in 
fig. 16 to the sheathing hyphae a. Since more than one trichogyne 
passed through a single stoma in the case in which he was working, 
Brooks concluded that more than one series of trichogynes was 
