Lamprothamnus alopecuroides , A. Braun. 65 
separable from the cells below, sometimes breaking off at a touch. The 
size attained by these cells of the 4 Vorkeimspitze ’ is very striking when 
compared with the cells of the leaves (Figs. 1 and 5)* The lowest cell 
sometimes attains a length of about 12 mm., whilst the middle cell reaches 
about half this length. 
The first leaf-node becomes divided by three vertical walls into four 
cells, from three of which superficial cells are cut off and develop into 
leaves. The fourth cell is regarded as an apical cell, which by further 
division and growth forms the stem of the plant. The cells of the leaf- 
node are cut off before the cells of the rhizoid-node, hence the leaves begin 
to develop before the rhizoid cells. 
From this first leaf-node (Uebergangsknoten, Pr.), which Pringsheim 
considers to consist of three imperfect nodes, each producing at most two 
leaves, arise the first true leaves (folia of Braun) of the young plant The 
4 Vorkeimspitze 5 becomes pushed to one side by the growth of the leaves, so 
that in older plants it has very much the position of a leaf, from which it 
is nevertheless distinguishable here by its great size, the constant number 
of cells, and the fact that no leaflets (foliola of Braun) are formed, as in the 
case of the other leaves. Only four leaves of the 4 U ebergangsknoten ’ or 
transitional node develop to any size, and of these the two leaves standing 
on each side of the apex of the pro-embryo are alike in size, and are larger 
than the other two leaves, which also resemble each other in size. The 
leaves of this whorl always remain uneven in length throughout the life of 
the plant. It can frequently be seen in older plants that in the two largest 
of the leaves of this node, the cell immediately below the uppermost cell 
becomes swollen, as in the corresponding cell of the 4 Vorkeimspitze 5 (Fig. 1). 
There is a tendency, especially in the lower nodes of the plant, for the cells 
to swell in the same way, the wall becoming gradually thinner as the cell 
expands. 
In one stem it was noticed that the first two nodes, which were separated 
by a long internode, bore leaves having swollen cells, whilst in the four 
succeeding nodes, which were close together, the leaves consisted of cells of 
normal size. In the nodes immediately above these, there again occurred 
long internodes and whorls of leaves having swollen cells. It is not 
uncommon for isolated leaves of a whorl, or even all the leaves of a single 
whorl, to show these swollen cells. 
These large cells are good objects for observing the fragmentation of 
nuclei. As in other Characeae there is in each nodal cell throughout life, 
and in all young cells, a single large nucleus, spherical in shape and generally 
having a single large nucleolus, though several nucleoli may occur. This 
nucleus lies embedded in the frothy protoplasm filling the cell : division to 
form new cells takes place karyokin etically. In the young cell, when cell 
formation has ceased, elongation begins and a single large vacuole is formed 
F 
