On THE PITHOPHORACES. 27 
only one sessile spore). Of P. kewensis nob. I have also found a spe- 
cimen (see pl. 1, fig. 8) of which the top cell supports a branch. It is 
possible, however, that this cell is not the real terminal cell of the plant, 
but that it has been made terminal by the breaths off in some way 
of the uppermost part of the specimen. 
What has been said above on the formation of branches concerns 
in the first place the normal branches, but also of the accessorial it 
may, in its principal points, be true. Only the following deviations are 
to be remarked regarding these. The place where they occur is, as 
we know, different from that of the normal branches. In most cases 
they are formed a small space above the base of their mother cell; and 
when this is the case, they increase downwards instead of upwards (pl. 
iene 418 ae; pl. 2) fig..9 ee; pl. 4, fig. 7, 9 ae). 1). By thisvcircum- 
stance they get quite the same relative position to the basal part of 
the mother cell, as the normal branches to the apical part. Only 
very seldom accessorial branches are found of another nature. Pl. 5, 
fig. 1 shows the lower part of a specimen, which possesses two acces- 
sorial branches, ac and ac’, which proceed both, it is true, from the 
lower part of their mother cells, but which are, nevertheless, placed 
considerably farther from the base of the mother cell, than accessorial 
branches usually are. What is most remarkable in these branches is, 
however, that they have increased not in a downward direction, but 
upwards, like the normal branches. Fig. 2 on the same plate also 
shows two accessorial branches, ac, attached in a rather uncommon 
place. — The accessorial branches generally remain unbranched; I have 
only once found one which was ramified (pl. 5, fig. 1 ac). Most fre- 
quently they appear on the principal filament of the cauloid and espe- 
cially on its lowest cell. Now and then I have, however, found acces- 
sorial branches proceeding also from branch cells. Pl. 1, fig. 18 ac 
shows an accessorial branch developed from a cell, belonging to a branch 
of no less than the 2:d degree. 
Ramification, accompanied by bipartition (by which act common 
branches, consisting of one or more cells, are formed), from terminal 
cells is, as we have seen above, upon the whole very rare in Pithophoracea. 
1) By comparison with the Cladophoree I have later come to the conviction, 
that the basal accessorial tranches ought to be regarded as bélonging to the root- 
system of the plant, being the morphological equivalents of the rhizines, emitted from 
the cauloid cells of the Cladophorca. See par. 5, pag. 37. 
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