35. Genus PTYCHOMITRIUM, Br. ^- Sch. 
Whole Plant — Perennial, densely csespitose, on rocks that are exposed, and on the ground, never on trees; foliage dark 
green, from 1 inch to 2 inches in height. 
Stem — Branched dichotomously upwards. 
Leaves — Lanceolate, concave, in eight rows, nerved to the apex, which is toothed; areolae dot-like in the middle and upper 
part of basal cellules, elongated and hexagonal. 
Inflorescence— Monoicous. 
Barren Flower (Antheeidia) — Gemmiform, axillary, elongated. 
Fertile Floiver (Archegonia) — Small paraphyses, filiform. 
Vaginula — " With a tubu,s vaginulus," Wilson. 
Capsule — Erect, terminal, elliptical, on a moderately long fruit stalk, pale brown. 
Calyptra. — Mitriform, furrowed, laciniated at the base, plicate. 
Operculum — Conical, with a long upright beak. 
Peristome — Single, teeth 16, bifid, long, erect, filiform, coloured. 
Annulus — Compound. 
Spores — Small. 
General Habitat — In mountainous places on rocks, sometimes on walls. Fruit : — March and April. 
Species Illustrated — Ptychomitrium polyphyllum (Br. & Sch.), Dicraaum polyphyllum (Smith). 
Reference to Plate — a, Plant, natm-al size ; aa, Same, X 2-in. ; 6, Stem leaf, x 2-in. ; c, Apex of same, X \-m. ; 66, Branch 
leaf, X 2-in. ; cc, Apex of same, X i-in. ; d, Basal cells, X i-in. ; dd, Mid-leaf cellules, X 1-in. ; e. 
Teeth of peristome, with portion of annulus, X i-in. ; /, Capsule, X 2-in.; .//, Same, X 2-in.; .7, 
Operculum, X 2-in. ; yij, Calyptra, X 2-in. ; h, Spores, X i-in. 
This genus is represented in Britain by the species figured. 
36. Genus ORTHOTRICHUM, Br. & Sch. 
Whole Plant — Perennial, growing on stones and trees in tufts, from :f inch to 1 j inches in height. 
Stem — Erect, occasionally procumbent, branched. 
Leaves — Lanceolate, concave, rigid ; margin recurved or revolute, when dry twisted, or ciirled ; areolae small, dot-like in 
the middle and upper parts of the leaf ; basal cells larger, diaphanous, hexagonal. 
Inflgkescence — Monoicous and dioicous. 
Barren Flower (Antheeidia) — Oval, varying in number, with long paraphyses. 
Fertile Flower (Archegonia) — Bud-like, few. 
Tagimda — 
Capsule — Erect, oval, cylindrical, or pear-shaped, having 8 or 16 strongly marked coloured striae. 
Calyptra — Campanulate, plicate, large, f m-rowed ; base laciniated, frequently covered with straight hairs. 
Operculum — Conical, short. 
Peristome — Single or double, composed of apparently 8 teeth, but really consisting of 32 very closely connected 
teeth. 
Annulus — None. 
Spores — Small, yellow. 
General Habitat — On rocks, walls, rails, and trees. Fruit : — Spring and summer. 
Species Illustrated — Orthotrichum afiine (Schrad.), in part, 0, Saxatile (Bridel),and 0. Bruchii (Bridel), in part. 
Reference to Plate — a, Plant, natural size, 0. affine ; 6, Stem leaf of same, X 2-in.; c. Capsule of same, X 2-in.; d, Oper- 
culum, X 2-in.; e, Calyptra, X 2-in.; /, Capsule, X 2-in. 0. Savatile, Portion of plant of same, X 
2-in.; hh, Calyptra, X 2-in.; cc, Stem leaf, X 2-in.; ee, Apex of leaf, X 1-in. ; g', Basal cells, X 1-in. 
ah, Plant natural size, 0. Bruchii ; ff. Capsule, X 2-in. ; dA, Calyptra, X 2-in. ; gg, Teeth of peristome, 
X 3-in.; h. Spores, X i-in. ; lih. Mouth of peristome, X 2-in. 
This genus is represented in Britain by twenty -nine species, according to Hobkirk. 
37. Genus ZYGODON, Eooh & Tayl 
Whole Plant — Perennial, growing in patches or tufts ; foliage bright green, covered with radicles, from J an inch to li 
inches in height. 
Stem — Having fastigiate branches. 
Leaves Spreading, lanceolate, carinate, with plane margin, the nerve reaching nearly to the apex ; arelose small, dot-like 
in the middle and upper portion of the leaf ; basal cells more elongated. 
Inflorescence — Monoicous, dioicous, and synoicous. 
Barren Flower (Antheridia) — Gemmiform, terminal. 
Fertile Flower (Archegonia) — Same paraphyses when present, filiform. , 
Vaginula — 
Capsule — Pear-shaped, erect, usually with 8 strias, on a straight fruit stalk. 
Calyptra — Cucullate, small, smooth, brown. 
Operculum — Flattish, beak long. 
Peristome — Present in some species, absent in others, when present having 8 inner and 8 outer teeth. 
Annulus — Indistinct. 
Spores — Smooth, small. 
Genekai Habitat — On rocks in Alpine situations and trunks of trees. Fruit : — Spring and summer. 
Species Illustrated — Zygodon viridissimus (Brid.), Gymnostomum viridissimum (H. & T.), and partly Z. Mougeottii. 
Reference to Plate — a. Plant, natural size, viridissimus ; aa, Same, X 2-in. ; 6, Stem leaf, X 1-in. ; c,Apex of same, X 
i-in. ; e, Basal cellules of same, X i-in. ; /, Capsule, X 1-in. ; //, Operculum, X 1-in. ; ah, Plant 
natural size, Z. Mougeottii ; g, Leaf of same, X 2-in. ; gg, Basal cellules of same, X i-in. 
This genus is represented in Britain and Ireland by six species, according to Hobkirk. 
12 
