572 
BAKER S NORTH YORKSHIRE. 
The SPHAGNACE^ or PEAT MOSSES. 
In connection with this group of plants, reference must 
be made to "The Sphagnaceae or Peat Mosses of Europe 
and North America" (1880), by Dr. R. Braithwaite, F.L.S., 
a treatise on this distinct family of plants, in which are 
excellent descriptions and figures of all the species then 
known, and which should be consulted by all students. 
We quote a few remarks from this work 
"The plants constituting the family Sphagnaceai, and 
known as Peat-mosses or Bog-mosses, have long attracted 
notice from the ordinary observer by their peculiar aspect 
and habit, and have equally interested the microscopist by 
the beauty of their tissues, and exercised the botanist by 
the difficulty which attends their correct determination ; the 
latter perhaps increased by the great variability of some 
species, and the uncertainty of the characters relied upon 
by various authors for the purpose of specific distinction." 
With regard to the function of these plants in the form- 
ation of Peat, Professor Schimper says : — " Unless there 
were Peat-mosses, many a bare mountain ridge, many a 
high valley of the temperate zone, and large tracks of the 
northern plains would present an uniform watery flat instead 
of a covering" of flowering plants or shady woods. For just 
as the Sphagna suck up the atmospheric moisture and 
convey it the earth, do they also contribute to it by pumping 
up to the surface of the tufts formed by them, the standing 
water which was their cradle, diminish it by promoting 
evaporation, and finally also by their own detritus, and by 
that of the numerous other bog plants to which they serve 
as a support, remove it entirely, and thus bring about their 
own destruction. Then as soon as the plant-detritus formed 
