26. Genus TRICHOSTOMLTM, Br. & Sch. 
Whole Plant — Perennial, from 1 incli to 3 inches in height, in patches on the ground, sometimes on stones ; habit of ToHula. 
Stem — Simple, or branched, flexuose, slender, fasciculate. 
Leaves — Lanceolate, lanceolato-subulate, with 5 to 7 or 8 in a row, in some species oblong-ligulate, obtuse, channelled, 
densely cellular; areolae round, dot-like in the upper part; basal cells elongated; nerve very thick and prominent, 
reaching to, or beyond the apex, and forming a short point. 
iNrLOEESCENCE — Monoicous and dioicous. 
Barren Flower (Antheeidia) — Terminal, gemmiform. 
Fertile Floioer (Aechegonia) — With styles and longish paraphyses. 
Vaginula — Oblong, cylindrical. 
Capsule — Oval, ovato-oblong, smooth, on a long fruit stalk, erect, coriaceous more or less. 
Calyptra — Smooth, cucullate. 
Operculum — Elongated, obliquely rostrate. 
Peristome — Single, with 32 long, erect, granulose teeth in unequal pairs, united together. 
Annulus — Simple or compound. 
Spores — Small. 
General Habitat — On chalky soil commonly near the sea, moist rocks, on clayey banks, and wet sandy situations. 
Fruit : — Throughout the year. 
Species Illusteated — Trichostomum tophaceum (Bridel), Didymodon trifarius (Hook. & Tayl.). 
Reference to Plate — a, Plant, natural size ; aa, Same, X 2-in. ; h, Stem leaf, X 2-in. ; ah, Branch leaf, X 2-in. ; c. Oper- 
culum, X 2-in. ; d, Cellules of mid-leaf, X ?-in. ; e, Basal cells, X i-in. ; /, Capsule, X 2-in. ; //, Teeth 
of Peristome, X i-in. ; g, Vaginula, X 1 -in. 
This genus is represented in Britain by eleven species, according to Hobkirk. 
27. Genus TORTULA, Schreb. 
Whole Plant — Perennial, or biennial, erect, from | inch to 3 inches or more in height ; yellowish-green ; gregarious. 
Stem — Caespitose, with innovations. 
Leaves — Ovate, lanceolate, crowded, suberect, or spreading, recurved or curved, carinate or concave ; margin entire, 
thickened, reflexed or inflexed ; nerve stout, commonly extending beyond the apex, and forming a hair-like semi- 
transparent point ; areolae very dense, dotlike, opaque ; in the upper portion of the leaf the basal cells diaphanous, 
quadrate. 
Infloeescence — Monoicous and dioicous. 
Barren Flower (Antheeidia) — Gemmiform, oblong, with filiform paraphyses. 
Fertile Floiver (ARCBSGomA) — With styles and moderately long paraphyses. 
Vaginula — Oblong. 
Capsule — Usually erect, cylindrical, or ovate, oblong, smooth, on a straight fruit stalk, red or reddish-brown. 
Calyptra — Cucullate, with a long beak. 
Operculum — Subulate, having a conical base and an oblique beak spirally arranged. 
Peristome — Having 32 long, filiform, twisted teeth, of a deep red colour, united by a narrow basilar membrane. 
Annulus — Wanting in some species, but where present comioosed of a single row of cellules. 
(Spores.— Varying in size. 
General Habitat — In chalk pits, on walls, stones and clayey banks, on limestone rocks, banks near the sea coast, about the 
roots and on the trunks of trees, and on thatched roofs. Fruit : — Throughout the year. 
Species Illusteated — Tortula muralis (Timm.). 
Reference to Plate — a, Plant, natural size; aa, Same, slightly magnified ; b. Stem leaf, X 2-in. ; bh. Same, x 1-in. ; c. Apex 
of leaf, X i-in. ; d. Capsule, X 1-in.; e, Archegonia, X i-in. ; /, Capsule, with calyptra, X 1-iu. ; //, 
Young capsule, x 2-in.; g, Calyptra, X 1-in.; h, Cellules of mid-leaf, X i-iu- ; i. Same, X a -in. ; hh, 
Basal cells of leaf, X i-in. ; ii, Same, X i-in. 
This genus is represented in Britain by thifty-two species. Some species are amongst our commonest mosses. 
28. Genus CIKCLIDOTUS, Br. & Sch. 
Whole Plant — Perennial, from 3 to 6 inches in height, growing in tufts and floating in the water, dark green. 
Stem — Having short fasciculate branches. 
Leaves — Lanceolate, thick, firm; margin thick; mid-leaf cells hexagonal; basal cells somewhat oblong. Perichxtial 
leaves — Large, tapering, and narrow, especially towards the apex, with larger oblong basal cells. 
INrLOEESCENCE — Dioicous. 
Barren Flower (Antheeidia) — Oblong, paraphyses filiform. 
Fertile Flower (Aechegonia) — Small, paraphyses filiform. 
Vaginula — Ovate. 
Capsule — Immersed, ovate or oblong, smooth, brown. 
Calyptra — Conical, erect. 
Opercul/um — Mitriform. 
Peristome — Single, with 32 long thread-like teeth, similarly twisted as in Tortula. 
Annulus — None. 
Spores — Olive-coloured, small. 
Geneeal Habitat — On wood and stones, in rivers and streams, local. 
Species Illusteated — Cinclidotus fontinaloides (P. Beauv.). 
Reference to Plate — a. Plant, slightly magnified : aa, Branch of same, X 2-in. ; h. Stem leaf, X 2-iii. ; hh, Perichietial 
leaves, X 1-in.; /, Capsule with vaginula, X 1-in.; d, Cellules of mid-leaf, X i-in.; g, Same, i-iu. ; 
//, Operculum, X 1-in.; g, basal cells of leaf, X §-in. ; h, Same, X j-in. 
This genus is represented in Britain by two species. 
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