THE MOSS 127 



128. Funaria, Mnium, Atrichum, or other common moss.* * Poly- 

 trichum has some advantages as a type on account of its size, 

 but the life history of a moss is more easily studied from some 

 of the smaller forms. Study the life habits of the type examined 

 and of such other forms as may be available (App. 19). 



A. The leafy moss plant. Note : 



1. The stem, bearing leaf-like scales generally called leaves. 

 What is their arrangement around the stem ? 



2. Rhizoids attaching the base of the plant to the substratum. 



3. The long-stalked sporophyte, also called the fruit of the 

 moss, arising from the tip of the moss plant and terminat- 

 ing in the large swollen spore case. If the spore case is 

 mature, cut it open to obtain the spores, or, if open, shake 

 out the spores. 



Show the above-given points in a habit sketch. 



B. The protonema and rhizoids. Carefully wash away the 

 earth around the base of a moss plant in a watch glass of 

 water and mount it with any accompanying green filamentous 

 growth. Examine under m.p. 



1. Note the filaments, green and brown, attached to the base 

 of the moss plant. The brown filaments are called rhizoids 

 and were once green, but the cells have largely lost their 

 protoplasmic contents and the cell walls have become 

 brown. The green filaments have the same structure as 

 other green filaments, which are to be found growing 



. freely over the substratum. They really form a part of 

 what is called the protonema. 



2. The protonema first arose from the germination of spores 

 developed in the spore cases of sporophytes, but additional 

 protonema may be developed from the base of the moss 

 plants. Draw the green and brown filaments under h.p., 

 comparing their cell structure carefully. 



3. Search for small buds which develop on the protonema 

 and grow into the leafy moss plants. Draw stages in their 

 development if possible. 



