454 THE BRITISH NATURE BOOK 



slender, graceful stalks, in the form of little stars, or like buds, concealed in 

 the axils of the leaves. 



The fruits consist of capsules containing a number of spores, but many 

 species bear no fruit, and are reproduced from little threads growing on the 

 leaves and in other ways. As in the case of ferns, the spores do not produce 

 the plants immediately, but certain minute green threads like the Conferva 

 of stagnant pools, and from these the mature plant is derived. 



The capsules, which every observer must have noticed on their stalks 

 springing upwards from the midst of the plant on an old wall or elsewhere, 

 and giving even at a distance a touch of golden or other colour, are most 

 remarkable in their mechanism and beauty. 



Under the microscope the capsule, which often is bright red or gold in 

 colour, is found to have a minute cap (calyptra). When this is removed a 

 second lid is found below (the operculum}, closely fitting, and in some cases 

 having a projecting tip or handle ! When this is taken away there is disclosed 

 a fringe of fairy-like fingers or teeth folded over the cup, and known as the peri- 

 stome. If breathed upon, this organ only contracts still more tightly, and the 

 only way to open it is to put it aside in a dry place, where, in a little while, 

 the teeth will open, spread out like rays, and reveal below the golden spores 

 which they have protected. This is a marvellous provision of Nature. It 

 does not exist, it is true, in all species, but is found in one form or another 

 in a large number. Its sensitiveness to damp causes it to close the cup when- 

 ever the air is moist ; but when fine, dry weather comes, it opens, and allows 

 the spores to escape and be carried away by the wind. 



The form of the peristome varies : it may be absent or rudimentary, or, 

 on the other hand, highly complex. The fringes or teeth are, however, always 

 four, or in a multiple of four, up to sixty-four. 



In one genus (Tortula) the fringes are thread-like and twisted together 

 like the strands of a rope. In another (Polytrichum) they are fixed to a central 

 disc, leaving openings in the side for the spores to escape. In the genus 

 Andrecea the whole capsule splits vertically into four, scattering its spores 

 by the violence of its opening. 



It is impossible to describe many of the species in simple words, for they 

 need expert dissection and examination ; but a few notes on some of the 

 commoner ones may start a student on this fascinating branch of Nature study. 



The POLYTRICHACE^, the highest developed of all the mosses, possess 

 certain peculiarities which enable them to be fairly easily identified. The 

 leaves have a stiff, bristly appearance, and the capsule is most distinctive. 



Polytrichum commune (the Common Hair Moss) is found on wet moors 

 and peaty bogs, growing sometimes as high as 18 inches. The capsules at 

 first are covered with fine hairs ; the operculum is pointed : it can be removed 

 with the point of a needle after being placed in boiling water, and underneath 

 will be found a disc, attached to the tips of the teeth of the peristome, which 

 grows from the capsule wall. 



