CHAPTER XI. 



BRANCH V. BRYOPHYTA. 



THE M0S8W0BTS. 



382. This Branch includes plants of much greater com- 

 plexity than any of the preceding. In very many cases 

 they have distinct stems and leaves, whose tissues often 

 show a differentiation into several varieties. In the sexual 

 organs the cell to be fertilized (the germ-cell) is from the 

 first enclosed in a protective layer of cells, and after fer- 

 tilization it develops into a complex spore-fruit. 



383. Mossworts are all chlorophyll-bearing plants, and 

 none are parasitic or saprophytic. They are of small size, 

 rarely exceeding ten or fifteen centimetres in height. They 

 generally prefer moist situations upon the ground, or on 

 the sides of trees or rocks. A few are aquatic. 



384. Two classes of Bryophytes may be distinguished, as 

 follows: 



1. Mostly thalloid creeping plants with splitting spore-fruits, and 



having elaters Hepatic^. Liverworts. 



2. Leafy stems, mostly erect, with spore-fruit opening by a lid, and 



having no elaters Musci. Mosses. 



Class I. Hepatic^ (the Jyiverioorts). 



385. In the Liverworts, the plant-body is for the most 

 part either a true thallus or a thalloid structure. When 

 there is a differentiation into stem and leaves, in most cases 

 the plant-body has two distinct and well-marked surfaces. 



