272 



SPOROPHYTE OF MARCHANTIA 



an umbrella-like structure (Figs. i86, 190). Owing to the ex- 

 tended growth of this latter branch, the archegonia come to lie 

 on the under side of the structure between the finger-like out- 

 growths, where they are completely hidden and protected by 

 fringed curtains, the involucre, that hang down from the fingers 

 (Figs. 191, 195, A). The antheridia retain their original position 

 upon the branch, where they appear in cavities, as shown in 

 Fig. 192. 



Fig. 193. Germination of the gametospore: A, section of a mature ar- 

 chegonium with canal cells dissolved, thus forming a passageway to the 

 large female gamete, g. B, sectional view of base of archegonium, show- 

 ing the germinating gametospore in two-cell stage. The perianth, p, is 

 seen growing up about the archegonium. C, later stage in growth of the 

 gametospore. The lower cell shown in B is forming stalk cells, while the 

 outer cell has produced densely granular cells that will later by further di- 

 vision form spore mother cells and elaters. 



The most important and significant departure in Marchantia is 

 seen in the germination of the gametospore which divides into an 

 inner and outer cell as in Ricciocarpus (Fig. 193, B). The inner 

 cell, however, by a series of divisions, forms a rudimentary stalk 



