Campbell. — Studies on some Javanese Anthocerotaceae. II. 95 
to judge from transverse sections of the young embryo they are somewhat 
variable in position. Fig. 25 shows three sections of a young embryo of 
six cells. In this case the upper region was divided into four cells, but 
they were not quite regularly disposed. The foot-region consisted at this 
stage of but two cells. Fig. 24 shows a nearly median longitudinal 
section of an 8-cel led embryo of the larger species, A, and in this case also 
the octant walls do not all fall in the same plane. The foot-cells have 
already begun to grow out into the root-like extensions, which later are 
so conspicuous. 
The differentiation of the columella (endothecium) is the same as 
in Anthoceros (Fig. 26), and the separation from the amphithecium of a 
single layer of archesporial tissue is also the same as in Anthoceros , except 
that, as was pointed out in D. B rente lii and D. crispus (Campbell, loc. cit.), 
the archesporial layer extends quite to the transverse wall that marks 
the upper limit of the foot. In this respect Dendroceros closely resembles 
Megaceros , which in some other respects is also more like Dendroceros 
than it is like Anthoceros. There are, moreover, further periclinal divisions 
in the apical part of the sporogenous layer which otherwise remains 
but one cell thick (Figs. 27, 28). This is, however, less marked than 
in Megaceros or Notothylas (see Text-figs. 1 and 2). 
The columella in the two Javanese species was better developed than 
in those from the West Indies, this being especially the case in species A. 
In cross section (Fig. 29), instead of the sixteen cells usually found in 
D. Breutelii there were sometimes nearly twice as many. Leitgeb figures 
a similar large columella in D. cichoracens. 
As in D. Brentelii and the other species studied by Leitgeb, the 
sporogenous layer, except above the apex of the columella, remains but 
one cell in thickness or very imperfectly duplicated in places. This is 
much like the smaller species of Anthoceros such as A. laevis. 1 In the larger 
species, e.g. A. Pearsoni (Text-fig. 2, C), the doubling of the sporogenous 
layer is complete. In Megaceros , which in so many ways closely resembles 
Dendroceros , there are from three to four layers of cells when the cell- 
divisions are completed (Text-fig. 2, B). 
Fig. 29 shows a transverse section of the sporogonium of species A 
some distance above its base. The large columella is surrounded by a 
single layer of archesporial cells, while the outer part of the sporophyte 
consists of from four to five layers of cells, which develop chlorophyll. 
The number of layers of cells in the wall may, in the larger species, become 
seven or eight. In no cases were stomata observed, and this agrees 
with all the other species of Detidroceros as well as with Megaceros . 
No rule could be made out as to the origin of the fertile and 
sterile cells of the archesporium. The spore-mother-cells can soon be 
1 See Davis, the Spore Mother Cell of Anthoceros, Bot. Gaz., xxviii, 1899. 
