104 



THE BOOK OF NATURE STUDY 



clear opening, as in Sphagnum, is closed by a series of reddish teeth ; 

 with the lens you can see sixteen of these teeth, with their tips meet- 

 ing at the centre of the mouth, and giving the latter the appearance 

 of an " iris diaphragm " (Fig. 21, B). When the air is dry the teeth 

 move apart, leaving slits between them through which the spores 

 escape as brown dust; when the air is damp the teeth become 

 more curved until they meet and close the slits. The stalk of the 



FIG. 21. Cord-Moss (Funaria). A, upper part of a male shoot ; B, peristome 

 seen from above ; C, female shoot with young fruit ; D, same with older 

 fruit. 



cord-moss shows peculiar movements when wetted and dried, 

 whence the name Funaria hygrometrica. You will notice that 

 the dry brown stalk is curved, wavy, or spirally coiled. Dip it 

 into water or moisten it with the tongue; the stalk untwists 

 itself, swinging the capsule round from right to left (seen from 

 above) ; you can easily tell the cord-moss from other mosses 

 by this peculiarity. 



