337 
MUSCI. 
ERY little was done in the investigation of the Mosses of 
Derbyshire until the nineteenth century was well advanced, 
and records in the preceding period are few and far between. 
These scanty notices, together with the subsequent more numerous 
records up to date, will be found in chronological order in the 
Introduction. The total number of species which have been up 
to the present time recorded is 3827. That so many should be 
found in the County is accounted for by its great vertical range 
from lowland to sub-alpine, the many kinds of rocks, the varied 
nature of the surface, grass land, arable, woodland, streams, 
rivers, extensive moorland, and rocky slopes and edges. 
Not a few species are of special interest owing to their ex- 
treme rarity in the County, notably Porotrichum angustifolium, 
for which the locality in Cressbrook still remains the only known 
station. 
Other species of great rarity are :— 
Seligeria tristicha b. dS, 
Ditrichum tenuifolium Lindb. 
Campylopus setifolius IWils. 
Grimmia Stirtoni Schimp. 
Pottia latifolia C.1. 
Tortula brevirostris B. & S, 
Weissia squarrosa C.J, 
Pleurochete squarrosa Linib. 
Zygodon Stirtoni Schimp. 
Discelium nudum Brid, 
Physcomitrella patens B. & S., v. Lucasiana Schimp. 
Physcomitrium sphericum Brid, 
Amblyodon dealbatus P. Beauv. 
Bryum uliginosum 2B. d 8. 
B. affine Lindb, 
