28 Vert Brecner Wrirrrock. 
But, on the contrary, ramification of the terminal cells without the for- 
mation of new cells is not at all uncommon. In this manner the helic- 
oids before mentioned, so characteristic especially in P. Cleveana nob., 
are generally formed. A terminal cell, sometimes belonging to the 
principal filament, but more frequently to a branch, sends forth at or 
near its top two or more, slender, irregularly shaped, more or less 
crooked processes. These are not separated from the mother cell by 
transversal walls, but will also in future belong as branchlets to the cell 
from which they have been sent forth. Simultaneously with this forma- 
tion of processes or branchlets, the greatest part of the chlorophyllaceous 
contents of the terminal cell passes from the lower part of the cell into 
its upper part. In this cell, two parts may consequently be easily 
distinguished, viz. a lower one of the common cylindrical shape and 
containing but a small quantity of chlorophyll-coloured protoplasm, and 
an upper one of a varying shape, but regularly ramified and containing 
an abundant supply of chlorophyll-coloured protoplasm. This upper part 
is the helicoid (pl. 5, fig. 4—7, 9, 11, 12 h). The helicoids are most 
frequently, but not always, formed by the ramification of terminal cells. 
Sometimes, though very seldom, they may be formed by the ramification 
of inclosed cells (pl. 5, fig. 1 4); and sometimes they may be formed 
without any ramification, only by a peculiar development of the upper 
part of an unbranched terminal cell; thus, that the upper part of the 
cell grows more tapering and also richer in chlorophyll (pl. 5, fig. 1 /’). 
Compare as to the rest paragraph 1, page 10. 
Having now almost completed the account of the formation of 
branches in the cauloid, it may seem fit to enumerate here in one place 
the different kinds of cauloid cells which do not, as a rule, form any 
branches. These are as follows: l:o the top cells, 2:0 the spore cells, 
3:0 the subsporal cells and 4:0 the cells belonging to that degree of 
branches which is, in each species, the highest (compare on this para- 
graph 1, pag. 6, 7). Regarding the top cells we have, however, seen 
above (pag. 26), that they now and then have the power to develop 
branches. The spore cells, on the contrary, are always devoid of this 
power. 7). But this does not prevent your finding, in almost all the 
1) After this was written I have, however, found in P. ocdogonia (Mont.) 
nob. (of which I have obtained the material missing before through the kind mediation 
of my friend, D:r* J. Rosrarinski), that even spores sometimes have the power of 
forming branches; see pl. 6, fig. 6, and the specific description of P. oedogonia 
(Mont.) nob. 
