FLOWERLESS PLANTS 



157 



A group of moss plants, showing the stalk (»S.) and 

 capsule (C.) of the spore-forming generation. 



commune)} Unlike some mosses, it often inhabits 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 presence of a great number of little upright stalks, 

 bearing at the summit 

 tiny capsules, which 

 seem to grow up from 

 the leafy moss plant. 

 The resemblance of a 

 large number of these 

 stalks and capsules to 

 a mimic field of grain 

 has given the name 

 pigeon-wheat moss to 

 this form. Take home 

 some of the moss plants 

 for study in the labora- 

 tory. Take care to 

 find not only the plants bearing stalk and capsule, but also certain 

 plants which terminate in a tiny rosette of leaves, this inclosing 

 what seems to be a very small flower. 



Leafy Moss Plant. — An examination of a leafy moss plant will show 

 that it has rhizoids or hairlike roots, an upright stem, and green leaves. 

 Make a drawing to show all the parts. 



Notice the stalk and capsule closely. The stalk grows directly from the 

 end of the leafy plant. This capsule is provided with an outer cap. The 

 cap, or calyptra, as it is called, seems to have somewhat the structure of a 

 thatched roof. Under the cap is found a lid, or cover, to the capsule. Re- 

 move the cover very carefully; notice whether it is attached to the 

 capsule. NoAv, turning the capsule upside down, tap it gently against the 

 surface of your drawing paper. The dust that escapes is made up of a 

 great number of spores. 



Sporophyte. — The capsule is the sporangium of the moss plant. The 

 stalk and capsule together form the sporophyte of the moss. 



If we were to plant the spores of the moss in damp sand, taking care to 

 keep the sand moist and warm, we might obtain germinating spores. The 

 spore germinates into a threadlike structure, very tiny, and not at all like 

 the adult moss plant. This thread is called a protonema. 



* See Hunter and Valentine, Manual, page 90. 



