CRYPTOGAMS 



387 



contain a number of stalked gemmse, flat, biscuit-shaped bodies of a green colour. 

 The gemmse arise by the protrusion and repeated division of a single epidermal cell 

 (Fig. 315) ; at maturity they become detached from the stalk (at x, Fig. 315,'D). 



Fig. 317.— Marchantia polymorphs. A, A female plant, with four archegoniophores of different ages ; 

 o, cupules (nat. size) ; B, under side of receptacle ; st, rays ; h, sheath ; sp, a sporogonium ( x 3) ; 

 C, half of a receptacle, divided longitudinally (x5) ; D, longitudinal section of a young sporo- 

 gonium ; spf, the foot ; sp, sporogenous tissue ; lew, wall of capsule ; aw wall, and h neck, of 

 archegonium ; p, pseudo-perianth ( x 70) ; E, ruptured sporogonium ; k, capsule ; s, spores and 

 elaters ; p, pseudo-perianth ; c, archegonial wall ( x 10) ; F, an elater ; G, ripe spores ( x 315) ; H, 

 germinating spore (s) ; vie, protonema ; It,, germ-disc, with the apical cell v and rhizoid rh ( x 100). 

 (C, E after Bischoff ; B, D, F-H after Knt.) 



They are provided with two growing points, one at each of the marginal constric- 

 tions, from which their further development into new plants proceeds. On cross- 

 section (E) they are seen to be composed of several layers of cells ; some of the cells 



