41. Gencjs DIPHYSCIUM, Weber & Mohr. 
Whole Plant — Small, resembling in appearance Pliascum cuspidatum, gregarious. 
Stem — If any, very short. 
Leaves — Linear or ligulate, entire ; nerve reddish, ceasing below the apex ; areolae opaque Perichxtial leaves — Lanceolate, 
structure and shape different, much larger ; nerve strong, eicurrent, reaching into a long serrated bristly point ; 
. areolae dot-like in the upper part, cellules at the base, quadrate, diaphanous. 
Infloeescence — " Dioicous " (Wilson), " Monoicous " (Br. & Sch.). 
Barren Flower (Antheridia) — G3mmlform, numerous. 
Fertile Flower (Archegonia) — Gemmiform , few. 
Vaginula — 
Capsule — Ovate, large, sessile, immersed. 
Calyptra — Mitriform. 
Operculum — Conical. " . 
Annulus — " Small." 
Spores — " Very small.'" 
General Habitat — Mountainous situations, on moist rocks, sometimes mixed with Jungermannia dilatata. 
Species Illustrated — Diphyscium foliosnm (Weber and Mohr.). Fruit : — August. 
Reference to Plate — a, Plant, natural size ; aa, Slightly magnified ; 6, Stem leaf, X 2-in. ; bh, Branch leaf, X 2-in. ; c, 
Periohoetial leaf, X 2-in. ; d, Apex of same, X 1-in. ; e, Basal cells, of same, X 1-in. 
This genus is represented in Britain by the species figured. 
42. Genus ATRICHUM, P. Beauv. 
Whole Plant— Perennial, erect, growing on soil, from 1 inch to 2 inches in height. 
Stem — Leafy ; rarely branched. 
Leaves — Lanceolate, undulated ; margiu thick, reddish, with spinose teeth, reddish; nerve reddish, reaching to the apex 
areote dense, roundish, or hexagonal under high power. 
Infloeescence — Monoicous and dioicous. 
Barren Floiuer (AtiTBERimA) — Oblong, terminal, cup-shaped, having filiform paraphyses. 
Fertile Floiver (AiiCBEGONii.) — Terminal, slender, few. 
Vaginula — Oblong. 
Capsule — .Cylindrical, erect, or cernuous, on a long fruit stalk, solitary, reddish-brown. ^ 
Calyptra — Cucullate, narrow. 
Operculum — Hemispherical, beak curved, long and slender, as long as the capsule. 
Peristome — Single, with 32 yellowish, short, obtuse, rigid teeth, somewhat incurved, of fibrous texture, united at 
the base. 
Annulus — None. 
(Spores— Small. 
Geneeal Habitat — On clayey soil in woods, on heaths and bare sandy places. Fruit : — Autumn and Winter. 
Species Illustrated — Atrichumundulatum (P. Beauv.), Polytriohum undulatum (Hedw.), and Bryum undulatum (Linn.). 
Reference to Plate — a, Plant, natural size; 6, Stem leaves, X 2-in.; c, Apex of leaf, X 2-in.; cZ, Portion of mid-leaf, X 
] -in. ; e. Teeth of Peristome, X l-in. ; f. Capsule, X 2-in. ; //, Operculum, X 2-ui. ; g, Cellules of leaf, 
X i-in. 
This genus is represented in Britain by four species, according to Hobkirk. 
43. Genus OLIGOTRIOHUM, De Gand. 
Whole Plant — Perennial, erect, not unlike Atrichum, but more rigid, from 1 inch to 1| inches in height. 
S I'EM — Leafy ; like Atrichum, not branched. 
Leaves — Lanceolate, inflexed, slightly crenulate near the apex ; nerve broad, prominent, with undulated or wavy lamellae ; 
areolcB small, round. 
Infloeescence — Dioicous. 
Barren Flower (Antheeidia) — Slender, fusiform, paraphyses filiform. 
Fertile Floiver (Aechegonia) — 
Vaginula — 
Capsule— 'Erect, ovate, subcylindrical, reddish, solitary. 
Calyptra — Cucullate. 
Operculum — Conical, short. 
Peristome — Single, with 32 teeth,very similar in shape and texture to Atrichum, but larger, colour pale-yellow. 
Annulus — None. 
Spores — Small, yellow. 
Geneeal Habitat — On barren soil, in Alpine situations. Scotland and Wales. Fruit : — July. 
Species Illustrated — Oligotrichum hercynicum (De Gand.), and Polytrichum hercynicum (Hedw.). 
Reference to Plate — a. Plant, natural size ; b, Stem leaf, X 2-in. ; hb, Portion of branch and leaves, X 2-iii. ; c, Apex 
of leaf, X 1-in.; d, Base of same, X 1-in,; e, Cellules of same, X i-in.; /, Capsule, X 2-in.; cc, Teeth 
of peristome, X i-in.; h, Spores, X i-iu- 
This genus is represented in Britain by the species figured. 
14 
