Order 1. Weisiaceæ. Peristome, with 16 teeth arranged in one series, rarely wanting. Leaf with midrib. Campylopus, Dicranum (D. scoparium, common in forests), Dicranella, Cynodontium.—Weisia, Gymnostomum (no peristome), Systegium.
Order 2. Leucobryaceæ. Peristome with 16 teeth. Leaves with three or more layers of cells, of which the external ones are air-conducting and perforated (as in the Sphagneæ), the middle one containing chlorophyll. Leucobryum.
Order 3. Fissidentaceæ. Peristome as in the preceding ones. The leaves are arranged in two rows on the plagiotropic shoots; in Fissidens the midrib of the leaf bears wing-shaped outgrowths. Conomitrium, Fissidens.
Order 4. Seligeriaceæ. Peristome with 16 undivided teeth. Very small Rock-mosses. Seligeria.—Blindia.
Order 5. Pottiaceæ. Peristome with 16 teeth, which are divided almost to the base, or with 32 teeth. Calyptra hood-like.—Barbula (B. muralis, B. ruralis), Trichostomum, Leptotrichum.—Ceratodon purpureus.—Distichium.—Pottia.
Order 6. Grimmiaceæ. The leaf-cells are often papillose; in the upper portion of the leaf, small, and of roundish shape. The calyptra is most frequently hood-like or conical. Eucalypta.—Orthotrichum, often with short-stalked capsule, is found on trees.—Coscinodon.—Hedwigia.—Grimmia, Racomitrium.—Cinclidotus.
Order 7. Schistostegaceæ. The stems are of two kinds (see above); Schistostega osmundacea, in caves, has a bright emerald protonema.
Order 8. Splachnaceæ. The capsule has a large, collar-like neck (see above). Splachnum (especially on manure).
Order 9. Funariaceæ. Capsule pear-shaped. Funaria (F. hygrometrica has a very hygroscopic seta, becoming twisted when dry, and straightening with moisture); Physcomitrium; Discelium.
Order 10. Bryaceæ. The capsule is thicker towards the apex; most frequently pendulous. Philonotis, Bartramia.—Aulacomnium.—Paludella Meesea.—Mnium.—Bryum, Webera, Leptobryum.