486 



BOTANY 



PART IL 



growth, and, as the archegonia are borne on these portions, they seem to arise from 

 the under side of the disc. The archegonia are disposed in radial rows between the 



FIG. 446. Marchantiu polymorpha. A, A female plant, with four archegoniophores of different ages; 

 b, gemma-cups (nat. size). B, Under side of receptacle ; st, rays ; h, sheath ; sp, sporogonium 

 (x 3). C, Half of a receptacle, divided longitudinally ( x 5). D, Longitudinal section of a young 

 sporogonium ; spf, the foot ; sp, sporogenous tissue ; kw, wall of capsule ; aw, wall, and h, 

 neck, of archegonium ; p, pseudo-perianth (x70). E, Ruptured sporogonium; k, capsule; s, 

 spores and elaters ; p, pseudo-perianth; c, archegonial wall (xlO). F, An elater. G, Ripe 

 spores (x315). I/, Germinating spore (s) ; vk, germ tube; k, germ-disc, with the apical cell v 

 and rhizoid rh ( x 100). (C, E after BISCHOFF ; B, D, F-H after KNY.) 



rays, each row being surrounded by a toothed lamella or sheath (perichaetium) 

 (B, 0, h). For structure of the archegonia see Fig. 436 and description. 



Fertilisation takes place during rain, the raindrops splashing the liquid on 

 the male discs which contains the spermatozoids, on to the female receptacles. 



