270 THE NORTHERN MICROSCOPIST. 

long ; it fruits both in March and October. The leaves are erecto- 
patent and narrowly lanceolate, gradually tapering into transparent 
(diaphanous) hair-points ; margins plane ; capsule pale, erect ; oval- 
oblong and partly exserted; lid short, conical, obtuse ; teeth of 
the peristome entire. Monoicous. 
A more rare species, although larger, is G. ovata, the oval- 
fruited Grimmia, known from the last by the leaf margins being 
recurved below, also by its reddish brown capsules and rostel- 
late lid. 
Very rare, with blackish glossy leaves is G. atrata, the black- 
tufted Grimmia. Found on Snowdon and Glen Callater. 
Another species, rare in fruit, is G. funalis, the Spiral-leaved 
Grimmia. Ben Lawers (Whitehead, Holt). 
The genus Grimmia is named in honour of Grimm, a German 
botanist ; sub-order Grimmiacez, Perennial acrocarpous Mosses, 
growing in tufts upon rocks, walls, and stones; with lanceolate 
leaves, Immersed capsule and conico-mitriform calyptras ; peristome 
single, with 16 equidistant teeth. 
Belonging to the family of Hair Mosses, Polytrichacez, two 
genera, Atrichum and Pogonatum, are in fruit this month. Atri- 
chum, a,$p.é, without hairs, is in habit intermediate between Poly- 
trichum and Mnium, and in the leaves and form of the flowers 
resembles Mnium undulatum, but is known from Mnium by the 
acute papillose character of the leaves. 
The calyptra is almost destitute of hairs, being spinulose at the 
apex only ; peristome single, of 32 teeth. 
A. undulatum, the Wavy-leaved Hair Moss, although a very 
elegant moss, is a common one, and one of the first to attract the 
moss student. Found in grassy, shady places, on soil only, it has 
long ligulate-lanceolate leaves, undulated in the margin and sharply 
toothed ; capsule cylindrical curved ; lid with a long curved beak. 
Monoicous, Fig. 20. 
In Britain, the male and barren plants only of A. crispum are 
found amongst the stones and grass beside streams, and although 
common round Manchester, principally on the millstone grit, the 
only recorded counties for this Moss are Lancashire, Cheshire, 
Yorkshire, Carmarthen, and Devon. The fertile plant has only 
been found in North America. The two remaining species are 
A. angustatum, rare, and A. tenellum, of doubtful nature. 
More showy plants than the preceding, and distinguished from 
them by the hairy calyptra, and by the more rigid, densely lamel- 
lated (covered with small plates) sheathing leaves is the genus. 
Pogonatum from zwywv, a beard ; easily separated from Polytri- 
chum by the rounded—not angular capsule, destitute of an 
apophysis. (See July notes, p. 183.) 2. xanum, the Dwarf Hair 
Moss frequents moist shady sandy banks, and has lanceolate leaves 

