152 Minnesota Plant Life. 



Arbor-vitae mosses. The arbor-vitae moss, developing pros- 

 trate branches of a peculiar fern-leaf aspect and growing in 

 moist woods, furnishes another example in which the egg-organs 

 are not terminal on the stem. The branch systems of this moss 

 are exceedingly beautiful objects. They consist of central 

 stems with lateral rows of shorter branches diminishing towards 

 the apex of the main axis, so that the whole branch-system looks 

 like a small green fern-leaf or feather. Sometimes three or four 

 of such feather-like branches are produced in a series, one at- 

 tached to another. Such a structure illustrates the develop- 

 ment of branches of different orders in the same plant-body. 

 The axial branches may themselves bear other axial branches 

 and these latter may bear the subordinated short branches. 



Tree-like mosses. In the tree-like moss which is found 

 growing near decaying logs in the forest or on dark wooded 

 banks, the axial branch stands erect like a little tree-trunk on 

 different sides of which are arranged the subordinated branches 

 so that the whole aspect of the plant is very much like that of 

 a miniature palm-tree two or three inches high. These tree- 

 like mosses have also another sort of stem which runs along the 

 ground a kind of rootstock from which the erect stems spring. 

 The leaves upon the trunk of the tree-like moss are brown scales 

 without leaf-green and it is only upon the secondary branches 

 the short branches that leaves with leaf-green are abun- 

 dantly formed. In high-types of moss plant-bodies a consid- 

 erable differentiation may exist between the kinds of stems. 

 There may be prostrate creeping stems, erect axial stems, di- 

 vergent secondary foliage stems, prolonged stolons extended 

 for propagative purposes, and special stems upon which the 

 egg-organs and spermaries are particularly aggregated. 



Carpet-mosses and pool-mosses. Among the mosses of this 

 highest division, the carpet-mosses which cover the surfaces of 

 fallen logs, peeling off regularly in carpet-like masses, furnish a 

 type in which a considerable variety of branching exists. Some 

 plants of the carpet-moss varieties are quite aquatic in their 

 habits, and are to be sought not so much in the running wa- 

 ter which the river-mosses frequent as in quiet pools among 

 algae, in overflowed meadows and in lakes. 



