CARPOSPOBE^. 137 



four parts or spores), or (3) conidia. The female organ in 

 the sexual reproduction is called the carpogonium, and the 

 male organ antheridium. Where two filaments cross each 

 other, or come iu contact, they enlarge (as in Sphcerotheea) ; 

 one assumes an oval form, becomes separated from the 

 filament by a partition, and represents the carpogonium 

 (Fig. 251, car) ; the other grows up in contact with the 

 carpogonium, cuts ofi" a small terminal cell, the antheridium 

 (Fig. 251, an). After fertilization the cells at the base 

 of the reproductive organs grow upwards, unite, and com- 

 pletely invest the carpogonium with a many-celled struct- 



ure, called the perithedum (Fig. 251, per). The carpogo- 

 nium (Fig. 251, ear) then undergoes cell-division, and from 

 it one asms (Fig. 251, as), or several (asci), are formed, 

 which contain the spores, sometimes called ascospores. 



171. The Florideae, or Eed Algse of salt water, are 

 chlorophyll-bearing representatives of the division Carpo- 

 sporese. The chlorophyll is concealed by a red pigment 

 (called phyeoerythnne), which is soluble in cold, fresh water. 

 When it is extracted the plants are green. These Algse are 

 very numerous and beautiful ; inhabit deep waters gener- 

 ally ; and are, therefore, difiicult to obtain for study. The 



Fig. 251. Successive stages (/, //, ///) in the development of the sporocarp in 

 Spkoeroiheca pannosa : cart carpogonium; a»j antheridium ; per, peridium. 



