CHAPTER V 



THE ANTHOCEROTE^ 



This order contains but three genera, Anthoceros, Dendroce^'os, 

 and Notothylas, and differs in so many essential particulars 

 from the other Hepaticae that it may be questioned whether it 

 should not be taken out of the Hepaticae entirely and given a 

 place intermediate between them and the Pteridophytes. All 

 the members of the order correspond closely in the structure of 

 the gametophyte, and while showing a considerable variation in 

 the complexity of the sporophyte, there is a perfect series from 

 the lowest to the highest in regard to the degree of develop- 

 ment of the latter, so that the limits of the genera, which 

 depend almost entirely upon the sporophyte, are difficult to 

 determine. The Anthocerotea^ are of extraordinary interest 

 morphologically, as they connect the lower Hepaticae on the 

 one hand with the Mosses, and on the other with the vascular 

 plants. Leitgeb ^ has endeavoured to show that they are 

 sufficiently near to the Jungermanniaceae to warrant placing 

 them in a series with that order opposed to the Marchantiaceae, 

 but a careful study of both the gametophyte and the sporophyte 

 has convinced me that this view cannot be maintained ; and 

 that while probably the affinities of the Anthoceroteae are with 

 the anacrogynous Jungermanniaceae rather than with the 

 Marchantiaceae, nevertheless the two latter orders are much 

 nearer each other than the former is to either of them. 



The gametophyte in all the forms is a very simple thallus, 

 either with or without a definite midrib. Of the three genera 

 Dendroceros is confined to the tropical regions, while the other 



^ Leitgeb (7), vol. v. p. 9. 



