BRYOPHYTA 101 



canal-cell become converted into a kind of mucilaginous material, 

 so that a spermatozoid can make its way down the neck to the 

 oosphere, and, fusing with it, form the zygote or oospore. 



The process of fertihsation is rendered possible by the fact 

 that the surface of the plant is generally moistened by rain or 

 dew. The liberated spermatozoid can make its way about in 

 this moisture, swimming by means of its cilia. It appears to be 

 attracted to the archegonium by the mucilaginous contents of 

 the neck, which escapes when the lid-oeUs of the neck separate. 

 This is said to contain a sugar, possibly cane-sugar, which is the 

 attractive matter. 



The oospore germinates at once, without becoming detached 

 from the archegonium. It divides into two ceUs by a wall, 

 knoviTi as the basal waU, forming an epibasal and a hypobasal 

 half. The former gives rise, by further segmentation and 

 division, to the body of the sporophy te, which is a capsule known 

 as the sporogonium. The hypobasal cell usually in a similar 

 way develops a structure known as the foot, which attaches the 

 young sporogonium to the gametophyte. There is no continuity 

 of tissue, however, between the two ; the foot forms a means of 

 attachment only, and serves to absorb nutriment from the 

 gametophyte. In some forms the foot is not developed from 

 the hypobasal cell, which does not divide at all, but remains 

 rudimentary and functionless. Then a foot is derived from the 

 lower part of the mass which is of epibasal origin. In the 

 Eicciese there is no foot, but both hypobasal and epibasal cells 

 go to form the capsule. Sometimes the capsule is developed 

 only from the upper part of the epibasal mass, the lower part 

 forming a more or less elongated seta or stalk. 



As this development takes place from the oospore in situ , 

 the growth of the sporophyte is attended by changes which 

 take place in the archegonium. The venter of the latter grows 

 as the sporophyte increases and forms an investment to it which 

 in the forms with sessile sporogonia, remains surrounding it till 

 the spores are ripe. In the stalked forms it is ruptured by the 

 elongation of the seta and carried up on the top of the capsule. 

 This investment is known as the calyptra. When it is ruptured 

 the part which remains at the base of the seta and forms a 

 sheath to it, is known as the vaginula. 



The body of the sporogonium soon shows a differentiation 

 into an external portion known as the ainphiihecium and an 

 internal part called the evdotheciuvi. In the higher forms an 

 air space arises in the inner part of the amphithecium, which is 



