152 



THE VARIOUS FORMS OF PLANTS 



rusts and smuts, causing plant diseases, and, most important of all, the 

 bacteria. We shall consider several of these plants later in their direct 

 relation to the human race. 



Mosses 



Mosses are mostly shade-loving and moisture-loving plants. They 

 form velvety carpets in many of our forests, but they often show their 

 preference for moist localities by covering the wooded shores of lakes 

 and swamps. 



Pigeon-wheat Moss. — One of the mosses frequently seen and easily 

 recognized is the so-called pigeon- wheat moss {Polytrichum commune). 



Unhke some mosses, it often iniabits dry 

 localities. It may be found on some dry 

 hillock close to the edge of the woods, 

 where it forms a reddish brown carpet. 

 This red color is due largely to the pres- 

 ence of a great number of little upright 

 stalks, bearing at the summit tiny cap- 

 sules, which seem to grow up from the 

 leafy moss plant. The resemblance of a 

 large number of these stalks and capsules 

 to a mimic iield of grain has given the 

 name pigeon-wheat moss to this form. 



Forms of Plants. — Three kinds of 

 moss plants appear to be present : leafy 

 plants, others bearing a stalk and cap- 

 sule, and still others which terminate at 

 the end in a little rosette of leaves, in- 

 closing what appears to be a tiny flower. 

 Leafy Moss Plant. — A leafy moss 

 plant has rhizoids or hairlike roots, an 

 upright stem, and green leaves. In the 

 plants which have a stalk and capsule, 

 the stalk grows directly from the end of 

 the leafy plant. This capsule is provided 

 with an outer cap which seems to have 

 somewhat the structure of a thatched 

 roof. Under the cap is found a Ud, or 

 cover, to the capsule. If this cover is 

 remo\ed and the capsule turned upside 

 down, the dust that escapes will be found 

 to be made up of a great number of spores. 

 Sporophyte. — The capsule is the 

 spore-producing part (sporangium) of the moss plant. The stalk and cap- 

 sule together form the sporophyte or spore-producing generation of the moss. 



Two moss plants, showing the 

 gametophyte (G) and the sporo- 

 phyte (S). 



