6 CHARACE^:. 



node immediately above it, and those in the lower part of the 

 intemode from the node below it. 



The organs of reproduction are very conspicuous by their colour 

 and form. They are always situated on the leaves, the plants 

 being very frequently monoecious. The antheridia (Fig. 61 B, a) 

 are modified leaflets or the terminal cell of a leaf; they are spheri- 

 cal and become red when mature. Their wall consists of 8 

 " shields," i.e. of plate-like cells, 4 of which cover the upper half, 

 and are triangular ; the 4 round the lower half, to which the stalk 

 of the antheridia is attached, being quadrilateral, with sides of 

 unequal length. The shields (Fig. 61 C) have dentated edges, 



FIG. 62. Chara fragilis : s apical cell ; FIG. 63. Oogonium of Chara : fc 



n, n nodal cells; in internodal cells; II, "crown"; u receptive spot; s sperma- 



II leaves ; r, r the cortical cells. tozoids. 



with the teeth fitting into one another, and their faces ornamented 

 with ridges. From the centre of the internal face of each shield 

 (C) a cylindrical cell, the manubrium, projects nearly as far as the 

 centre of the antheridium ; at the inner end of each of the manu- 

 bria a spherical cell, the capitulunt, is situated. Each capitulum 

 bears six secondary capitula, from each of which four long coiled 

 filaments (C, D) project into the cavity of the antheridium. 

 These filaments are divided by transverse walls into from 100-200 

 discoid cells, in each of which a biciliated, coiled spermatozoid is 

 developed (D, E) from the nucleus. The spermatozoids escape 

 from their mother-cell and are set free by the shields separating 

 from one other. 



