354 



BOTANY. 



below, where there are two layers. The neck of the arehe- 

 gonium at first contains an axial row of cells, but these 

 become dissolved and transformed into a mucilaginous mass 



just before the time of 

 fertilization. The germ- 

 cell lies in the lower 

 swollen portion of the ar- 

 chegonium ; it consists of 

 a naked rounded mass of 

 protoplasm. At the time 

 of fertilization the upper- 

 most cells of the neck of 

 the archegonium diverge 

 from one another, and 

 thus form an open chan- 

 nel to the germ-cell. 



463.— Fertilization 

 takes place in the water, 

 or in the presence of a 

 considerable amount of 

 moisture. The sperm ato- 

 zoids, which are produced 

 in great numbers, move 

 through the water by 

 means of their A'ibratile 

 cilia, and some of them 

 find their way down the 

 channels of the archego- 



Fte! m-Dey'ei'opment of the eporogonium "i*. ^here thcy unite their 

 >f AM»■^a%<7^•om€«)TO^^,longitlldmalscc- substance with the germ- 



tion of the avchegouium, 6, 6, shoi-tly after fer- o 



tilization ; A, neck;/; npirnl portion of young cclls. As a result of this 



eporogonium ;/■', basal portion of young sporo- . ^ 



gonium, A vertical section of a female flower ; UUlOn, the germ-CcU SUr- 



/; young sporogonium elongating, and carrying i -j. li -i.! n 



up the remains of the old archegonium, o (now I'OUnQS Itsell Wlul a Wall 



called the calyptra) ; A, neck of old arcnego- t it i j 



nium. C, a later stage of the same. In B aiid 01 CellulOSC, and SOOU Un- 



C the sporogonia are seen to be growing down- ■ /lp,,o.„p„ fqiviainn in vnvmna 



ward into the tissues of the leaTy stem ^x CiergOes OlVlSlOn in VanOUS 



600 ; B and Cmuch less.-After Sachs. directions, giving rise to a 



many-celled mass, the young sporogonium (/, /', Fig. 343, 

 A). In most Mosses the young sporogonium elongates rap-, 

 idly, and while its upper end carries up the remains of 



