LIVERWORTS AXD MOSSES. 



59 



for these are gre;it on account of its ra[)id growth and the 



su]j]jly required as reser\e for 



each spore. The foot, being in 



close contact with the tissue of 



the gametophvte, acts as an 



absorbing organ, receiving food 



solutions from it. The sporo- 



phyte thus lives, in part at least, 



as a parasite upon the gameto- 



phyte. 



In some mosses there is a ten- 

 dency to increase the nutritive 

 work of the sporophyte b\- de- 

 veloping at tlie top of the stalk, 

 below the spore-case, a mass of 

 green tissue. InBryumf.-J, fig. 

 72) this gives tlie capsule a pear- 

 shape, while in Splachnum (B, 

 C, D, fig. 72) it is so fiir de- 

 veloped as to exceed the spo- 

 rangium. In some species it is 

 expanded into a miniature um- 

 brella which, one can imagine, 

 might readily become segmented 

 into leaves. 



The intimate attachment of sporophyte to gametophvte 

 continues throughout the life of the former. Sometimes the 

 gametophyte perishes at the close of the growing season, but 

 more commonly it is perennial, growing and branching at the 

 anterior end as the older posterior parts die away. 



Fig. 73. — Vouni; sporophyte of Pkas- 

 ciini cuspidatriin. c. columella ; y, 

 foot, embedded in gametophyte stem; 

 .r, seta (cells not shown) ; sps^ spo- 

 rangium ; sp. spore-mother-cells. 

 Ma^rnitied 80 diam. — .\fter Kienitz- 

 Geriorf, 



