CRYPTOGAMS 



181 



plant body is very thin and much expanded, and reaches a 

 length of several feet. In most cases the plants are 

 attached by more or less rootlike holdfasts. The often 

 beautiful color is due to the presence of a red pigment, 

 which more or less completely masks the chlorophyll. 



434. Reproduction. A characteristic method of bearing 

 spores is in groups of four (Fig. 299), each group result- 

 ing from the division of the contents of 



an original mother cell. Such spores are 

 termed tetraspores. They are bright red 

 bodies without cell walls, and being un- 

 provided with cilia, are dependent upon 

 water currents for dissemination. 



435. Reproduction, with fusion of the 

 reproductive cells, may be illustrated by 

 the case of Nemalion ; this being taken 

 as a simple instance of a process which 



e in some members of 



the group becomes 

 highly complicated. 

 The reproductive cells of Nemalion are 

 pollinoids, naked spherical cells pro- 

 duced singly in rounded antheridia 

 (Fig. 300, a), and 

 differing from an- 

 therozoids only in 

 being unciliated ; 

 and egg cells formed 

 within elongated 

 cells termed carpo- 

 gonia (Fig. 300, <?). 

 The egg occupies 

 the enlarged basal 

 portion of the car- 

 pogonium, the hair- 

 like extremity of 

 Several pollinoids, 



299. Tetraspores () 

 in a filament 

 of Polysipho- 

 nia. 



B O 



300. Nemalion: A, showing the earpogonium (c), 

 trichogyne (t) with pollinoids near, and 

 antheridia (a) ; B, after fertilization, the 

 carpogonium beginning to hranch ; G, the 

 nearly mature spore-bearing body (cysto- 

 carp, c?/). THUBET. 



which is known as the trichogyne (f). 



brought by circulation of the water, may adhere to the 



