112 STUDY OF COMMON PLANTS. 



LIVERWORTS. Hepaticce. 



The liverworts are closely allied to the mosses, their 

 cycle of development being essentially identical with that 

 of the latter group. Accordingly our work will be re- 

 stricted to a comparison of the general characters of some 

 of the most easily procurable liverworts. Representatives 

 of the genera named at the beginning of this section are 

 widely distributed and easily obtained through a con- 

 siderable part of the year. Lunularia is of almost uni- 

 versal occurrence in greenhouses, and while seldom if ever 

 found in fruit, almost always has gemmse in different 

 stages of development. Conocephalus is common and 

 abundant in moist, shady places. The floating species of 

 Riccia have a wide range, as do also some of the species 

 of Porella. These and other genera will furnish a full 

 supply of material for comparative study. 



The student is advised to proceed with his preliminary 

 observations as he did with the mosses, comparing a num- 

 ber of different kinds, instead of confining his attention 

 to a single species. Differences of habit between these 

 and the mosses, the bilateral and dorsi-ventral frond of 

 the liverworts, their texture and anatomical structure, and 

 peculiarities of fructification should all be noted. If the 

 mosses have already been studied as directed, there will 

 be little difficulty, with suitable material and the help of 

 the various manuals, in obtaining a corresponding general 

 view of the-structure and habits of the liverworts. 



Many interesting subjects for more extended investi- 

 gation present themselves ; among them the following 

 are suggested as 



