Calobryum Blumei , N. ab E. 5 
is inclined to believe that Leitgeb’s interpretation is the correct one 
(see Fig. 1). 
A notable character of the stem structure of Calobryum , pointed out by 
Goebel, is a differentiation of the tissues into an outer region, or cortex, 
composed of cells containing numerous starch granules, and a conspicuous 
central cylinder made up of more or less elongated cells, almost destitute of 
granular contents (Text-fig. 1, A). A cross-section of the stem resembles 
closely that of a typical moss, and it is highly probable that the colourless 
axial cells have to do with water conduction, as Goebel believes to be the 
case. So far as the writer is aware, no other foliose Liverwort possesses this 
moss-like stem-structure. 
Numerous short mucilage-secreting hairs occur in almost all parts 
of the plant. They usually consist of a short base, made up of one or two 
cells, and a terminal secreting cell, which is elongated, pear-shaped, and with 
dense granular contents (Text-fig. 1, b). Where the stem is perfectly 
erect, the leaves are inserted horizontally, and one cannot always tell which 
of the three rows of leaves is the ventral one. In other cases, probably 
where the shoot is inclined, the leaves are obliquely inserted, and those of 
one row are decidedly smaller, and may be compared with the amphi- 
gastria of the foliose Jungermanniales (Fig. 2). How far this difference 
in the arrangement of the leaves is due to the influence of ligh remains to 
be seen, but it is highly probable, as Goebel suggests, that this is the 
determining factor. 
The Reproductive Organs. 
The reproductive organs are formed in considerable numbers at the 
end of the leafy shoots, and apparently archegonia and antheridia are never 
formed together. The leaves surrounding the group of reproductive 
organs are large, and are especially conspicuous in the male ‘ inflores- 
cence’, which, as indicated before, bears a remarkable resemblance to 
that of such a moss as Mnium. 
Within the three large perichaetial leaves surrounding the archegonia 
there are two or three smaller upright leaves which quite conceal the 
archegonial group. 
The most remarkable feature about the reproductive organs is the 
extraordinary similarity in the early development of archegonia and 
antheridium, which for some time are so much alike as to be quite in- 
distinguishable. 
Leitgeb 7 states that in Haplomitrium the early divisions of the an- 
theridium conform to the usual type of the Jungermanniales; but in 
Calobryum this type is unusual, and in most of the very young anthe- 
ridia examined the early divisions were exactly like those in the arche- 
1 Loc. cit., p. 72. 
