84 



ELEMENTARY STUDIES IN BOTANY 



the sporophyte is dependent upon the gametophyte, and is 

 never an independent plant. In the higher groups (Fern- 

 plants and Seed-plants) the sporophyte is an independent 

 leafy plant. In some way, the dependent, 

 leafless sporophyte of Bryophytes becomes 

 the independent, leafy sporophyte of 

 Pteridophytes (Fern-plants), and the liver- 

 wort Anthoceros has a sporophyte that 

 has suggested the way. Just as Liver- 

 worts are more important than Mosses 

 in the history of the plant kingdom, so 

 are the Anthoceros forms the most im- 

 portant Liverworts in the history, al- 

 though they are the least abundant. 



From what has been said, it is evident 

 that any sporophyte of the Bryophytes 

 that shows a tendency to become inde- 

 pendent is on the way towards an inde- 

 pendent sporophyte, and when complete 

 independence is attained the sporophyte 

 no longer belongs to Bryophytes. The 

 peculiarity of the Anthoceros sporophyte 

 is that it is more nearly independent than 

 the sporophyte of any other bryophyte. 

 This sporophyte does not consist of a 

 roundish spore-case on a more or less 

 elongated stalk, as in other Liverworts 

 and in the Mosses, but elongates without 

 a stalk, until it resembles a small grass- 

 blade (Fig. 67). The most striking fact, 

 however, is not its form, but that it is as 

 green as a grass-blade. The presence of 

 chloroplasts means that this sporophyte is able to manu- 

 facture food, and although it has a bulbous foot sunk in 

 the thin body of the gametophyte (Fig. 68), it does not 



FIG. 68. Anthoceros: 

 longitudinal section 

 through the sporo- 

 phyte (broken into 

 three regions), show- 

 ing the bulbous foot 

 imbedded in the 

 gametophyte, and 

 the three regions of 

 the sporophyte 

 above : (1) the green 

 region (four layers 

 of cells), (2) the 

 spore-producing re- 

 gion (the stages in 

 spore-formation may 

 be observed by trac- 

 ing this region from 

 below upwards), and 

 (3) a central region. 



