Anthocerotales. 
34 7 
joined end to end and forming definite elaters with a well-marked 
spiral band ; there are no stomata on the capsule. In some 
species the spores begin to germinate before being set free, 
forming multicellular bodies, as in Pellia and Fegatella. 
Notothylas shows a close general resemblance to Anthoceros in its 
gametophyte and sexual organs, but the sporogonium presents some 
interesting points of difference and has given rise to much discussion 
and conflicting opinion. Lang’s recent work on this genus (20) has 
added considerably to our knowledge of the sporogonium and its 
development. The earlier observers Milde (26, 27, 28) and Gottsche 
(12) held that the columella of Notothylas might either be present 
or absent in different plants of the same species, and that it might 
be either intact and well-developed in mature or nearly mature 
capsules, or might be broken into fragments, or represented by a 
short projection at the base of the capsule. Leitgeb confirmed 
these observations, but showed that when the columella was absent 
this was not due to breaking up into its constituent elater-like cells, 
as Gottsche had suggested. Leitgeb further concluded that while 
the first divisions of the embryo were like those of Anthoceros , the 
central (endothecial) cells cut off by the first periclinal walls gave 
rise to the archesporium and that the columella was subsequently 
differentiated within this central tissue or endothecium. Leitgeb 
found the columella well developed in some specimens of N. 
Breutelii, while in others there was hardly a trace of it even at the 
base of the capsule, and on the view that the whole sporogenous 
mass is derived from the endothecium and the columella arises by 
later differentiation within it. he suggested that this genus forms a 
link between the other Anthocerotales on one hand and the Junger- 
manniales on the other, comparing the columella of Notothylas to 
the axile bundle of sterile elater-like cells which springs from the 
base of the capsule of Pellia. 
According to Mottier (29) and Campbell (2) the development of 
the sporogonium in Notothylas orbicularis is much the same as in 
the other Anthocerotales, except that the archesporium becomes 
very massive in its upper part where it extends over the apex of 
the columella. These writers confirm Leitgeb’s account, however, 
as to the regular alternation of alternate zones of sterile and fertile 
tissue in the archesporium, and the occurrence of curved thickenings 
on the sterile cells and also on the cells composing the columella. 
Lang’s account is much more complete and conclusive, and he sums 
up the chief features of the sporogonium in the species he investi- 
