Hepaticte of North America. 11 



Elaters. Enclosed in the capsule with the spores are 

 certain thread-like bodies formed of a single cell, and contain- 

 ing from one to four spiral (rarely annular) bands in their 

 walls. These are the elaters, and probably aid in scattering the 

 spores when the capsule matures and its valves separate. In 

 Anthoceros they are often of peculiar shape, simple or jointed, 

 and usually without distinct fibres. 



In the last named genus occurs another organ known as 

 the columella, which is found in no other group of Hepaticce, 

 but reappears as a constant organ in the true mosses. 



CLASSIFICATION 



General Relations. The hepatics form a part of a nat- 

 ural group of plants which stands about midway between the 

 highest and lowest forms of vegetable life. Indeed, in them 

 are mingled forms representing the two vegetative types the 

 one thall&jphytic, with merely a plant body without true foliage 

 the other cormophytic, having the differentiation of stem and 

 leaves more or less complete. 



In the seven recognized divisions of the vegetable kingdom 

 the Bryophyta, to which the hepatics belong, is placed fifth in 

 a lineal classification, as follows: 



I. PROTOPHYTA. Bacteria, yeast plant, etc. 

 II. ZYGOSPORA. Diatoms, desmids, moulds, etc. 



III. OOSPORA. Many freshwater and marine algae. 



IV. CARPOSPORA. Red algae, Chara, lichens, mushrooms, 



many parasitic fungi. 

 V. BRYOPHYTA. Hepaticae, mosses. 

 VI. PTERIDOPHYTA. Ferns and their allies. 

 VII. PHANEROGAMIA. Flowering plants. 

 A lineal classification, however, does not properly present 

 the natural position or inter-relations of the Hepaticae and other 

 groups, and indeed the affinities of the lower groups are too 

 imperfectly understood to represent even a tolerable natural, 



