480 Campbell. — Studies on some Javanese Anthocerotaceae. /. 
The sporogonium may become very long, this being especially so in 
M. Tjibodensis , where it may attain a length of 9 cm. or possibly more. 
In M. Salakensis it is much shorter, but in both it is stout and the amount 
of sterile tissue large. To correspond with this development of the assimi- 
lative tissue the foot becomes very large, and at an early period develops 
extensively branched rhizoid-like outgrowths (Figs. 42, 47), which penetrate 
between the adjacent cells of the thallus. Sections through the older 
sporogonium show the different stages of development of the sporogenous 
tissue, as there is of course the same basal zone of meristem by which the 
growth of the sporogonium is brought about. Transverse sections, where 
the spQrogenous layer is first clearly differentiated (Fig. 58), show the square 
columella, its cells more or less rounded, and exhibiting small intercellular 
spaces. Surrounding this is the single clearly defined row of archisporial 
cells. The sterile amphithecial tissue shows four or five rows of cells 
outside the archesporium. Higher up the archesporium divides into two 
layers, and still higher up these divide again more or less completely, so 
that there are three or four layers of cells (Fig. 54). In M. Salakensis the 
development of the archesporial tissue is somewhat less than in M. Tjibo- 
densis , and there are seldom more than three layers of cells in the completed 
archesporium (Fig. 57). 
Soon after the final divisions of the archesporial tissue are complete 
the differentiation of the sporogenous cells and the elaters begins. There 
seems to be no definite relation of these to the divisions of the archesporium, 
such as can be seen in Notothylas , and in some species of Anthoceros. 
Certain cells (el) are longer than the other (sp). The latter soon begin to 
become rounded off and to separate, while the sterile cells rapidly increase 
in length with the growth of the sporogonium, and push their way between 
the young spore-mother-cells which thus lie in the meshes of a net-work 
formed by the coherent elongated sterile cells (Figs. 6o s 61). The separa- 
tion of the spore- mother-cells is due to a disintegration of a part of the 
original cell-wall, which evidently becomes mucilaginous, and this mucilage 
stains very strongly, and makes the sporogenous tissue extremely conspicuous 
in stained sections. 
The young spore-mother-cells are nearly round, with a small nucleus 
which does not stain very strongly. At an early period the single chroma- 
tophore can be easily seen. Owing to its small size the divisions of the 
nucleus are difficult to study, and no attempt was made to follow out the 
details of the nuclear division. They probably do not differ much from 
what has been observed in Anthoceros (Davis, The Spore Mother Cells of 
Anthoceros. Bot. Gazette, xxviii, 1899). Davis found four chromosomes in 
the nucleus of Anthoceros. As in Anthoceros , the division of the chroma- 
tophore occurs before the nucleus divides. The nucleus of the young cell 
lies near the centre, more or less enclosed by the cup-shaped chromatophore 
