THE BRYOPHYTA 



135 



The female plants are very 

 small and not in any way con- 

 spicuous. The leaves converge 

 together at the top, forming a 

 bud within which the archegonia 

 are contained (Fig. 62, A). They 

 arise from the cells of the 

 growing-point, and the apical cell 

 among others is itself used up 

 to form an archegonium, so that 

 no further direct growth of the 

 vegetative axis is possible. Here, 

 however, as in the male plant, 

 the growth may be continued 

 later by means of a lateral bud. 



The cell from which an arche- 

 gonium is to be formed first 

 divides by a transverse wall. 

 The further growth is by means 

 of the apical cell, which in this 

 case gives rise to four rows of 

 segments, three of which are 

 peripheral and form the wall of 

 the archegonium, while the 

 fourth row is central. From 

 the lowest cell of the central 

 row, the ovum and ventral 

 canal -cell (see Fig. 62, ) are 

 produced ; the rest of the series 

 of central cells form the canal 

 of the neck. The external seg- 

 ments undergo further transverse 

 and vertical divisions; the wall 



B 



FIG. 62. A, longitudinal 

 section through the apical 

 bud of a small female plant ; 

 a, archegonia ; b, leaves. 

 Magnified 100. B, a single 

 archegonium ; v, the en- 

 larged venter, within which 

 the ovum and ventral canal- 

 cell are seen ; from n to m 

 is the neck, enclosing the 

 neck - canal. Magnified 

 550. C, unripe spermato- 

 zoid in its mother-cell, and 

 mature spermatozoid with 

 two cilia. Magnified 800. 

 (After Sachs.) 



