BRYOPHYTES 



83 



Anthoceros. Among the Liverworts there is a group of 

 which Anthoceros may be used as a representative. The 



body is a prostrate 

 sheet of cells, some- 

 times lobed but not 

 leafy, and resembles 

 the bodies of many 

 Liverworts (Fig. 67). 

 It is not complex either 

 in structure or in form, 

 but it has a remark- 

 able sporophyte. It 

 is believed by many 

 that this represents the 

 kind of liverwort spo- 

 rophyte that gave rise 



B 



FIG. 66. Diagrams illustrating the evolution of 

 the sporophyte among Bryophytes: A, sporo- 

 phyte of Riccia, being only a spore-case ; B, 

 sporophyte of Marchantia, showing a reduced 

 amount of sporogenous tissue, and the sterile 

 cells forming a short stalk; C, sporophyte of a 

 leafy Liverwort, showing further reduction of 

 sporogenous tissue and corresponding increase 

 of sterile (stalk-forming) tissue ; D, sporophyte 

 of Anthoceros, showing further decrease of spo- 

 rogenous tissue and increasing complexity of 

 capsule and stalk (including foot) ; E, sporo- 

 phyte of a Moss, showing extreme reduction of 

 sporogenous tissue and great complexity of cap- 

 sule and stalk; the numerals (1-1) indicate the 

 first wall of the dividing egg (note that in A 

 and B the two halves of the egg contribute 

 almost equally to the sporophyte ; that in C 

 one-half of the egg produces the sporophyte ; 

 that in D the first wall is vertical ; and that in 

 E almost all the sporophyte is produced by 

 one-half of the egg. 



FIG. 67. Anthoceros: the pros- 

 trate body bearing long and 

 narrow sporophytes ; the two 

 sporophytes to the left are 

 mature and have split to 

 discharge the spores. 



to the higher groups of plants. If this is true, such a 

 sporophyte deserves special attention. 



Throughout the Bryophytes (Liverworts and Mosses), 



