306 



XXII. REPRODUCTION OF ALG^I. 



ment of the internode. From the lower nodes arise the long, 

 branched, obliquely septate rhizoids. The branches and so-called 

 "leaves" are, in the main, repetitions of the stem. The sexual 

 organs are produced laterally at the nodes, and we will study 

 them in the widely-spread species Char a fragilis, which fruits 

 freely in early summer. 



Antheridia of Cham. The antheridia of C. fragilis are re- 

 cognisable even with the naked eye as red globules, with a 



FIG. 112, Chara fragilis. B, entire lateral axis with branches of the third order 

 at the nodes, at each of the lowest four of which stands an antheridium (a), and 

 oogonium (o) (x 6). A, median longitudinal section through a lateral axis r, and the 

 sexual organs arising from it ; a, antheridium, of which na is the basal node ; p, the 

 stalk and m the manubrium ; ob, an oogouium or nucule, of which po is the stalk-cell, 

 no the nodal cell, v the " Wendungszelle," and c the crown (x 90). 



diameter of about ^ of an inch. They stand singly, turned 

 downwards, on the inner side of the branches, in their middle 

 line (Fig. 112, A, a and B, a), and occupy the position of a 

 twiglet. The female organ, the oogonium, or nucule (Fig. 112, 

 A, ob and B, o), is found singly, close above the antheridium, and 

 arises from the lowest node of the same twiglet which is developed 

 into an antheridium. The antheridia have a complicated structure. 



