349 

 SPHAGNA. 



WM. INGHAM, B.A., 



York. 



This is an old Greek name for some plant, thought by some 

 to be sage, by others to be a lichen. The singular number is 

 Sphagnum, a name first applied to these plants by Dillenius. 



The popular names are Bog mosses, because they are so 

 common in bogs ; Peat mosses, because they form a con- 

 stituent of peat ; and Sphagnum mosses by those who use them 

 in the treatment of soldiers' wounds. 



Each plant is so delicate that it cannot stand upright by 

 itself, and so we find the peat mosses in compact colonies in 

 which the individual plants are close together and thus support 

 one another. This compact growth leads to another im- 

 portant result, for it keeps the moisture, so important to these 

 plants, within the tufts, and so well is this done that even in the 

 driest summer the peat mosses are found to be wet if trod upon. 



If the plants float on water, there is no need for compact 

 masses, so in this case single plants are found floating. 



Each plant, when dry, is lighter than a feather, on account 

 of its very loose cellular structure, which is very beautiful under 

 the microscope, and reminds one of very delicate lace-work. 



One peat moss alone contains thousands of delicate leaves, 

 all sessile on the main stem, and numerous branches. The 

 leaves on the main stem are nearly always of different shape 

 and structure from those on the branches, and these branches 

 are mostly in tufts, some of the branches spreading out, and 

 others lying along the main stem. 



To aid in the diffusion of moisture the leaves in most cases are 

 perforated by numerous pores, beautifully seen when a leaf is 

 soaked in methyl violet, and then transferred to the microscope. 



These mosses may be easily recognised in a walk over a 

 moor, by their usually paler colour than the surrounding 

 vegetation. They particularly delight in growing under the 

 shade of heather, which must be drawn aside to see them. 



The branches at the top of the stem are very much shortened 

 and form a kind of head, known as the capitulum. By river 

 sides, where sand has been deposited, the peat mosses are 

 sometimes buried up to their capitula. 



They often drape the sloping wet cliffs, and in this case the 

 capitula point downwards. Early in the year they may be 

 seen growing under water on the beds of pools, and in this case, 

 should they be entangled with other vegetation such as 

 Pilularia globulifera, they always remain on the bed, and can 

 only be approached when the pool dries up. 



They are of varied colours — white, green (the commonest 

 colour), brown to nearly black, ruby-red, yellow, violet, purple, 

 grey, flesh-coloured, rose-coloured, and sometimes variegated 



1917 Nov. 1. 



