196 



THALLUS OF GREEN ALG.^ 



from them not uncommonly undergoing no further division. 

 Branching originates by the outgrowth from the upper ends 

 of the cells, just beneath the septa, of small protrusions which 

 are cut off to form the apical cells of the new branches 



--af. 



Fig, 104. — Cladophora. A, Small part of a plant of C. glomerata (after 

 Migula). B, Attaching cell (after Brand). C, Apex of a branch with 

 three zoosporangia, the top one having liberated its contents through 

 the aperture seen on one side (after Oltmanns). D, Single cell stained 

 to show nuclei («.), pyrenoids (p-), and the net-like chloroplast (c. 

 (after Wettstein), E, Small part of a cell showing the manner of in- 

 growth of the septum (cf. p. 24) separating two daughter-cells (after 

 Strasburger). 



(Fig. 104, A) ; the degree of branching varies greatly in the 

 different species and even in different individuals. 



The lowest cell of the main C/rtrfo/)/;ora-filament is modified 

 as an organ of attachment, has scanty contents, and is often 

 considerably branched (Fig. 104, B). Basal attaching cells 



