3 
Calobryum Blumei, N. ab E. 
shoots (Fig. i, k). From the bases of these leafy shoots, as well as 
from the prostrate portions of the rhizome, horizontal leafless branches 
are formed, which continue the rhizome, which is thus seen to be sympo- 
dial in character. 
The stem grows from a tetrahedral apical cell, like that of Treubia y . 
or of the foliose Jungermanniales. Goebel figures both longitudinal and 
transverse sections of the stem apex, and the writer’s preparations agree 
perfectly with Goebel’s figures. Haplomitrium , to judge from Leitgeb’s 
account and figures, closely resembles Calobryum in the form of the 
apical cell. 1 
Seen in cross-section (Text-fig. 2, F), the apical cell appears trian- 
gular in outline, one side being somewhat shorter than the other two. 
Presumably the shorter side is ventral in position. In longitudinal sec- 
tion the lateral faces are strongly curved, and converge above so that 
the outer free surface of the apical cell is relatively small (Text-fig. 2, a). 
Goebel’s Fig. 25 of the apex of a rhizome branch shows the apical 
cell to be deeper and narrower than that of the leafy shoot. 
Each segment of the apical cell in the upright shoots gives rise 
to a leaf. The leaves, as Goebel pointed out, differ from those of most 
Liverworts in being thickened at the base. In this respect Calobryum 
resembles Treubia , but it is not likely that this indicates any near relation- 
ship between the two genera. 
The first wall in the young segment divides it into an outer and 
an inner cell (Text-fig. 2 , a). From the outer cell is developed the outer 
thin portion of the leaf, while the inner cell, by further division, gives 
rise to the thickened leaf-base and the portion of the stem between it 
and the next older leaf. The line dividing the apical and basal regions 
of the young leaf is very clearly defined (Text-fig. 2, A-C). 
Sections of the very young leaf parallel with the surface (Text- 
fig. 2, b) show what looks like an apical cell from which a series of 
basal segments have been cut off. This apical growth, however, is no 
longer evident in older stages (Fig. c), and the subsequent growth of the 
leaf is probably due largely to the activity of cells near the base. In 
the upper part of the leaf the divisions are in two planes only, so that 
it remains but one cell thick ; but in the basal region, where the cells 
are much larger, divisions may be in all directions, and there is thus 
formed a thickened basal zone. In the older leaves the thickened basal 
region merges gradually into the thinner part of the leaf. 
The stem, as already stated, consists of two parts, the rhizome-like 
basal portion and the upright leafy branches. The rhizome, as Goebel 
pointed out, is sympodial. From the base of the leafy shoots there are 
produced leafless branches which may themselves give rise to similar ones. 
1 Leitgeb : loc. cit. 
