328 Campbell. — Studies on some East Indian Hepaticae. 
The earlier stages of the embryo were found only in D. velutina ; but 
as the later stages in D. trichocephala agree very closely with those in 
D. velutina , it may be assumed that there are no very great differences in 
the young embryos of the two species. 
The fertilized egg, after developing a membrane about itself, becomes 
elongated and divides by a transverse wall into two cells, of which the upper 
one is larger than the lower (Text-fig. 6 , a, c). The next division is also 
transverse instead of vertical as is usual in the Marchantiaceae. In this 
respect Dumortiera closely resembles the figures of Plagiochasma , described 
by Meyer. 1 A similar condition has been described for Targionia by 
Miss O’Keefe, 2 but all of the writer’s preparations of the young embryos of 
Targionia show the typical quadrant formation. 3 
It is not unlikely that a second transverse wall may be formed in the 
upper cell of the embryo before any vertical walls appear, but this is not 
certain. Each of these primary cells is next divided into quadrants by 
intersecting vertical walls, but these quadrants are not entirely symmetrical 
(Text-fig. 6 , G). 
The original hypobasal cell gives rise to the foot, and to part, at least, 
of the short seta. In this region the divisions are quite irregular (Text- 
fig. 6 , E, f), but in the epibasal portion of the embryo a series of periclinal 
walls is formed, separating the central sporogenous area from the wall of the 
future capsule. The terminal segment, however, does not develop any 
sporogenous tissue, but contributes only to the wall of the capsule, which at 
the apex is thicker than it is at the sides. 
As the young sporophyte grows it becomes oval or pear-shaped in 
outline, and the sporogenous region or archesporium becomes clearly 
defined. In this region longitudinal divisions predominate, so that the cells, 
especially towards the centre of the sporogenous tissue, are much elongated 
(Text-figs. 7, 8). These cells as usual stain more strongly than the sterile 
tissues of the sporophyte. The young wall of the capsule consists for the 
most part of a single layer of cells, but at the apex of the capsule it consists 
of two or three layers, forming a sort of cap. These parietal cells have less 
dense contents than the adjacent sporogenous tissue. The latter soon shows 
a differentiation into spore mother-cells and young elaters. The spore 
mother-cells are usually in more or less regular rows, due to the repeated 
transverse divisions of some of the archesporial cells, while the others remain 
undivided and develop into elaters. 
The lower part of the sporophyte develops a short seta merging 
gradually into a not very well-defined foot. The seta is somewhat better 
1 Loc. cit., Figs. 35, 36. 
2 O’Keefe, Lillian : Structure and Development of Targionia hypophylla. New Phytologist. 
vol, xiv, 1915, pp. 105-16. 
3 Campbell : loc. cit., Fig. 23. 
