204 
readily discernible on the surface of the embryo capsule (fig. 10) 
make, in the judgment of the writer, the induction that the de- 
hiscence is spiral so safe and certain that he has felt no hesitation 
in so describing it and in basing the generic name upon this char- 
acter. The absence of thickenings in the walls of the 
cells of the capsule valves is noteworthy. Schiffner states* of 
all the /ungermaniaceae akrogynae: “Die reife Kapsel besitzt 
eine aus 2 bis mehr Zellschichten bestehende Wand, deren Innen- 
schicht in ihren Zellen stets Verdickungsleisten enthalt.” In 
Gyrothyra, the transverse walls of these cells usually appear a 
trifle thicker than the longitudinal, but the walls are otherwise 
wholly without traces of local thickening. 
In respect to structure of the sporogonial envelopes, Gyrothyra 
is one of several very interesting transitions from the ordinary Jun- 
germania type to the various pouch-bearing genera. Considered 
from this point of view and from certain other gametophytic 
characters, its nearest affinities are undoubtedly to be found in 
that section of Wardia represented by Nardia haematosticta (Nees) 
‘Lindb., of Europe. In manner of dehiscence of capsule it recalls 
the marsupiiferous genus Kazta; but the valves of Gyvothyra are 
much longer and their cell-walls lack the local thickening, while, 
of course, no generic comparison of the two can be made so far 
as the gametophyte is concerned. 
It is with pleasure that the author associates with this novel 
plant the name of one who, by his numerous papers upon the 
American Hepaticae, as well as by his unfailing generosity, has 
placed the younger workers in the same field under lasting obli- 
gations. It should be noted that, although Professor Macoun’s 
specimens were without the capsules, which reveal the distinctive 
generic character of Gyrothyra, Professor Underwood had already 
recognized that they represented something undescribed. 
Explanation of Plates 302, 303. 
1. Entire 9 plant. \ 5. 
2. Cauline leaves. )< 18. 
3- Marginal and adjacent leaf-cells. >< 225. 
__ 4, Transverse section through marginal portion of leaf. ae 216. 
_ §- Underleaves. >< 24. 
oo * Engler and Prantl, Nat. Pf. Fam, 1: Abt. 3, 71. . nah as os 
