
NOTES ON MOSSES. 183 

-The best known amongst the mosses is the wall screw-moss, 
which takes possession of our walls in a very short time, eyen in 
our largest towns, This genus, named Tortula, from tortus, 
twisted, and now renamed Barbula, is easily recognised by its 
peristome of 32 long filiform teeth, twisted from left to right round 
the apex of the columella, while the species B. muralis is very 
marked from the long obtuse leaves, with strongly recurved margin 
and nerve excurrent into a distinct hair point. Monoicous, cap- 
sule erect, oblong, lid with a short conical beak. Resembling 2. 
muralis in size and aspect, but whose leaves have a thickened 
border, is Z: marginata, the border-leaved screw-moss. It is found 
on sandstone walls, and is rare. 
The other Tortulas in fruit this month are Z. convoluta, convo- 
lute screw-moss, and Z. revoluta, revolute screw-moss, both on 
walls, chiefly limestone. 
ZT. levipila, smaller-hairy screw-moss, on trunks of trees. 7 
subulata, awl-leaved screw-moss, on sandy hedge-banks, &c. ; and 
TL. tortuosa, curly-leaved screw-moss, on rocks, chiefly limestone, 
not common in fruit, but frequent about Matlock. 
A very useful moss in the domestic economy of the Laplanders 
is Polytrichum commune, the common hair-moss. Linneus tells us 
they use it for their beds, and highly praise it for not harbouring 
insects or any infectious disease ; and another writer says the bear 
lines his winter quarters with a thick bed of the same moss, The 
Polytrichaceze, like the Pogonatums, are distinguished by their 
hairy calyptras, whence the name Hair-moss from zodAvé, many, 
and Op.é, hair; but their capsules, instead of being round like 
Pogonatum, are four, five, or six-angled, and have a discoid apo- 
physis or swelling at the base of the capsule. Capsule at first 
erect, horizontal when ripe, lid rostrate, the beak variable in length, 
straight or oblique. Peristome of 64, rarely 32 teeth; stems from 
two inches to six or eight inches in height; leaves lanceolate, 
horizontally inserted. Growing in dry or moist uncultivated places, 
especially in heath and wood, and the whole of the genus, of 
which there are seven species, fruiting in summer, with the excep- 
tion of P. sexangulare, which is not ripe until September, and is 
known by its spreading incurved entire leaves, with the margins 
reflexed. . gracile, slender hair-moss, is very similar to P. com- 
mune, but smaller and more slender and with a shorter capsule, of 
which the angles are very obtuse and indistinct. PP. commune is 
known by its acutely four-angled capsule and its distinct apophysis ; 
both /. commune and P. gracilis have sharply serrated leaves. 
L. juniperinum, juniper-leaved hair-moss, P. strictum, and P. pilt- 
Jerum, bristle-pointed hair-moss, have their leaves bristle-pointed 
with entire, inflexed, broad margins, capsule quadrangular. 
Many of the Bryums and Mniums are in fruit this month, the 
