CARPOSPOREM. 
node, the ascending and descending lobes dove-tailing in a prosenchymatoiis manner. 
The formation of the cortex takes place so early that the elongating internode is 
covered by it from the first, the lobes keeping pace with its extension in length and 
thickness. Each lobe continues to grow, like the stem, by means of an apical cell, which 
becomes segmented by transverse septa ; out of each of the segments cortical internodal 
and nodal cells are formed by repeated divisions. The latter divide, by successive -septa, 
into an inner cell (Fig. 194, D,c), in contact with the internode of the stem, and three 
outer cells, the middle one (/) of which commonly grows into the form of a spine or 
knob, resembling a leaf. The outer lateral cells (n n) of the cortical node, on the other 
hand, following the elongation of the internode itself, grow into longer tubes, so that 
each cortical lobe consists of three parallel rows of cells, the middle row however 
containing alternately short and long (internodal and nodal) cells. The cortex of the 
leaves is derived from the leaflets, and its formation is much simpler (Fig. 193, C-E, br). 
From the basal nodes of Chara other foliar structures also arise, both on the inner and 
outer side of the base of the leaf (Fig. 192, 6), which Braun calls Stipules; they are 
always unicellular, and are sometimes very short, sometimes elongated. 
The nodes are the parts from which all the lateral members of the Characese 
originate. The root-like structures or RhizoUs spring from the outer cells of the 
Fig. 194.— Development of the cortex of the stem of Chara fragilis ; A a very young- internode of the stem with the 
cortical lobes r still consisting of one cell ; R—D its further development ; r r signifies in all the figures the cortical lobes 
that ascend from the lower, r' r' those that descend from the upper leaves ; v v the apical cell of each cortical lobe ; ^ its 
internodal cells ; n m n the commencement of the formation of the node ; D c the central cell of a cortical node ; 5 signifies 
ia all the figures the unicellular ' stipules' which spring in pairs from the base of the leaves. 
lower nodes of the primary shoot, and consist of long hyaline tubes growing obliquely 
downwards, and elongating only at their apex. They are formed by the outgrowth 
of flat cells at the circumference of the node, and are therefore attached to it by 
a broad base; but the bases of the stouter rhizoids themselves divide still further, 
giving rise, especially at the upper margin, to small flat cells from which slender 
rhizoids are developed. The rhizoids are segmented by only a few septa which lie 
far behind the growing apex, and have at first an oblique position. The two ad- 
joining cells abut upon one another like two human feet placed sole to sole. The 
branching always proceeds only from the lower end of the upper cell (Fig. 195, B)\ 
a swelling is here formed which becomes cut off by a wall, and by further division 
produces several cells which grow into branches; these therefore stand on one side 
like a tuft. The tubular cells composing the rhizoids attain a length of from several 
millimetres to more than two centimetres, with a thickness of from 4V to yV nim. 
The Vegetative Reproduction of Characeae always proceeds at the nodes, and has 
three modifications: — (i) Tuberous formations called Bulbils (starch-stars) which occur 
in Chara stelligera. They are isolated underground nodes with greatly abbreviated 
