MOSSES 21 



cluster close to the ground, as also by its con- 

 spicuous, pear-shaped spore-vessel, formed at the 

 end of a long, flexible stalk, which is frequently 

 much curved ; this spore-vessel, when ripe, forms a 

 particularly beautiful object under the microscope. 

 Marshes and Bogs must always have an attrac- 

 tion for the moss-hunter, for here he may meet 

 with some of the most beautiful of our species, 

 such, for instance, as the exquisite Bog-mosses 

 (Sphagna), those pale green, wet, spongy plants 

 that are so familiar to frequenters of our Scotch 

 and Welsh mountains. No words can do adequate 

 justice to the extreme beauty of these Bog-mosses, 

 as seen against a black background under the 

 microscope, when, owing to the delicate structure 

 of the leaves, and the practical absence of colour, 

 they have all the appearance of being formed of 

 some silvery-white material of almost unimagin- 

 able fineness. The cell-formation of the Sphag- 

 num leaf is exceptionally large and open, thus 

 enabling the plant to retain a considerable amount 

 of water, to which fact it owes its spongy character. 

 Plate VII. fig. 41 is a drawing of a small piece of 

 a leaf of the Blunt-leaved Bog-moss (Sphagnum 

 cymbifolium), one of the commonest of the family ; 

 this is magnified 140 times, and thus shows very 

 clearly the large, peculiarly shaped cells to 

 which I have referred. The Pointed Bog Feather- 

 moss (Hypnum cuspidatum) is also common in 

 these moist regions; its glossy leaves are pale 



