272 



BOTANY. 



carpogonium, is a single cell, wide below, and tapering above 

 into a long slender canal, the trichogyne, which is open at 

 its apex {A, og, Fig. 183). The carpogonium is the terminal 

 cell of a branch, which in its development swells up, while 

 at the same time elongating into a tube. In the swollea basal 

 portion there is a considerable mass of protoplasm, which is 

 the essential part to be fertilized. 



The male organs, the antheridia, are formed as flask-shaped 

 protuberances which grow out of adjoining cells ; they be- 



Fig. 183.— CWeoctefe pulvvnata. A, portion of fertile plant ; an, antheridia ; og, 

 carpogonia — each with a irichogym^ ; z, z, epermatozoids ; h, hairs, with sheathing 

 basee. TV, fertilized carpogonium surronnded by covering, r ('' pericarp"), the whole 

 constitnting the sporocarp. C, sporocarps burst open, BnowiQg the interior tissue, 

 8ch ; r. cortical cover (" pericarp J. D, zoospore.- (swarm-spores) from C. X 350. — 

 After Priugsheim. 



come cut off from the cells from which they grow, by trans- 

 verse partitions. In each antheridium a single oval bi- 

 ciliate spermatozoid is formed [A, z, z, Fig. 183). 



363.— Fertilization is doubtless effected by these sperma- 

 tozoids coming in contact with the protoplasm of the carpo- 

 gonium, but the actual entrance of the former has not yet 

 been seen. After fertilization the protoplasmic mass in the 

 carpogonium increases considerably in size, and becomes 

 sun-ounded by a cellulose coat of its own. The cells which 



