8 KEY TO THE FAMILIES OF MOSSES 



Plants of moist shady places, growing in dense tufts or cushions; 

 leaves showing but one kind of cells (except in section) ; capsules 



elongated, with a peristome Leucobryaceae 



3 — Leaves in two rows, with edges apparently towards the stem 4 



Leaves in more than two rows, or if apparently two-ranked the 



edges of the leaves are not toward the stem 5 



4 — Leaves apparently split on the inner edge and sheathing each other 



and the stem, costate; peristome present Fissidentaceae 



Leaves ecostate, not split at base, but forming a continuous wing- 

 margin along the stem in the sterile plants; peristome lacking. 



Schistostegaceae * 



5 — Acrocarpous 6 



Pleurocarpous 21 



6 — Plants black or blackish green, except at top of growing stems; leaves 



with very thick cell-walls; growing on trees or rocks 7 



Plants green to light yellow-green, sometimes hoar) 7 , or, if blackish, 



grow ing on soil 9 



7 — Capsule dehiscing by four valves, as in the Hepaticae, almost ex- 

 clusively alpine or subalpine Andreaeaceae 



Capsule dehiscing by an operculum; peristome of 16 jointed teeth. ... 8 

 8 — Peristome single (very rarely lacking), with teeth not united in pairs, 

 but usually perforate or bifid, richly colored and rarely reflexed 

 when dry. Plants often hoary with colorless leaf apices, nearly all 



growing on rocks Grimmiaceae 



Peristome double (with one or two exceptions), teeth often united in 

 pairs, rarely perforate, usually reflexed when dry, inner peristome 

 of linear erect segments. Plants very rarely hoary, mostly tree- 

 grow ing Orthotrichaceae 



9 — Peristome of four large distinct unjointed teeth Georgiaceas 



Peristome having an inner plaited cone; outer peristome of shorter 

 jointed teeth often present. Odd plants, best recognized by a 



reference to the illustrations Buxbaumiaceae 



Peristome lacking, or of more than four teeth 10 



10 — Peristome of 32 to 64 non-articulate teeth; calyptra densely hairy 

 with long whitish hairs (except Cathannea); leaves with numerous 

 vertical lamellae on the upper surface of the costa. Plants large 



and very often dark colored, growing on soil Polytrichaceae 



Peristome when present consisting of 16 to 32 plainly articulate teeth, 



frequently lacking 11 



11 — Minute stemless plants with cleistocarpous capsules and usually 



persistent protonema Ephemereae of Funariaceae 



Plants with stems, a few cleistocarpous or gymnostomous but mostly 

 peristomate; protonema usually evanescent 12 



* Not listed. 



