PEEFACE TO LIST OF MOSSES, &C. 
xiii 
rich botanical district, and some of the rarest of our flower- 
ing plants, as well as mosses, are recorded from this district. 
The Upper parts of the rivers Swale and Ure amongst 
the western hills are also suitable localities, and many inter- 
esting species are recorded from the tributary streams in the 
higher parts of these rivers. 
With the aid of several botanical friends who have been 
studying the mosses and have sent me specimens collected 
from various districts, many additions have been made to 
the list of mosses known to grow in North Yorkshire, which 
now comprises 389 species of Urn mosses, and 29 Sphagnums, 
making a total of 418 species, which is an increase of 109 
since 1863. There are also a good many varieties noticed. 
In addition, a list of 124 species of the Hepaticae is given, 
none of which were included in the first edition of North 
Yorkshire. Pearson's " Hepaticce of the British Isles" has 
been mostly followed for the arrangement and naming of 
these. The Hepaticae prefer sheltered glens, or grow on 
moist heathery ground amongst Sphagnums, where there is 
abundant moisture. Some of* the rarest are found in the 
vicinity of waterfalls, the spray from which constantly keeps 
them moist. 
In August, 1 90 1, Messrs. Jones and Horrell visited Upper 
Teesdale, and spent nearly a month collecting the Sphag- 
nums which grow very abundantly in the bogs of that 
elevated moorland region. The results of their investigations 
are published in the Journal of Botany for 1903.* 
In this account 28 species and 81 varieties are named 
which had been gathered, and from this list many additions 
have been made to the flora of North Yorkshire. The 
annual rainfall on the higher hills at the upper parts of the 
rivers is much greater on the western hilis than on those of 
♦ "The Sphagna of Upper Teesdale," by E. C. Horrell, F.L.S., p. 180. 
