adapted from: How to Know the Mosses and Liverworts; H.S. Conard; Wm.C. Brown Company; 1979.
This key is intended to enable a person to determine the genus of most mosses that are typically collected in most of North America. It is not comprehensive.
No attempt has been update nomenclature in this version. However the synonyms pages on this website can help translate genera for use with other references. I find viewing these genera as sensu lato makes some IDs easier by presenting them as traditional morphological groups.
1a Whitish plants with cells of two kinds throughout the leaf; large empty cells in 2 or 3 layers, with small green cells in between -- 2
1b Green, brown, yellow, or blackish plants; if empty cells occur, they are not in 2 or 3 layers or they occur at the base, apex, or margin of leaf -- 3
2a Leaves crowded, grooved on the upper side; green cells 4-sided in cross section -- Leucobryum
2b Leaves widely spreading, flattened, particularly at the ends of stems; green cells 3-sided in cross section -- Octoblepharum
3a (1b) Leaves inserted on the stem in two rows -- 4
3b Leaves inserted in three or more rows though plants sometimes strongly flattened thus appearing in two rows -- 7
4a Leaves appearing split at the base consisting of two vaginant laminae which clasp the stem as well as the base of the leaf above; wing-like laminae extending dorsally and apically -- Fissidens
4b Leaves not divided into vaginant, dorsal, and apical laminae -- 5
5a Sterile plants with leaves pinnately lobed and connected by broad decurrent bases, not sheathing or subulate; growing in damp caves and basements -- Schistostega
5b Leaves filiform from a sheathing base and narrowed into a linear awn -- 6
6a Linear awn smooth; peristome absent -- Bryoxiphium
6b Linear awn rough; peristome present -- Distichium
7a (3b) Plants with a peristome of 4 teeth; sterile plants with stems commonly ending in a gemma cup; leaves costate and with isodiametric cells -- Tetraphis
7b Plants with a peristome of more than 4 teeth or the peristome absent; gemmae when present at the tips of sterile stems not arranged in a cup -- 8
8a Leaves small, rarely seen; plants bearing a flat, red-purple capsule obliquely or horizontally attached to a rough seta 1-2 cm long -- Buxbaumia
8b Leaves well developed and persistent -- 9
9a Capsule sessile (without a seta), inclined, asymmetric, immersed in bristle-tipped perichaetial leaves; leaves of sterile stems ligulate, rounded at apex, crisped when dry -- Diphyscium
9b Capsule and leaves not as above -- 10
l0a Plants stemless or with a very short stem; capsules without an operculum; ephemeral -- 11
l0b Plants with or without a distinct stem; capsule when present with an operculum or regularly dehiscing near middle; mayor may not be ephemeral -- 17
11a Leaf margins involute -- Astomum
11b Leaf margins not involute -- 12
12a Capsules short-pyriform, emergent to shortly exserted -- Bruchia
12b Capsules more or less spherical, without a neck -- 13
13a Plants bulbiform, often appearing 3-angled, reddish; leaves broadly ovate, deeply concaved or keeled; spores large, 40-50µ in diameter -- Acaulon
13b Plants not bulbiform or 3-angled; leaves linear to lanceolate, flat to slightly concave -- 14
14a Leaves setaceous -- Pleuridium
14b Leaves narrow or broad but not setaceous -- 15
15a Plants surrounded by branching, velvety protonema; leaf cells smooth or coarsely uni-papillose -- 16
15b Plants not surrounded by conspicuous protonema; leaf cells pleuri-papillose; leaves broadly lanceolate to oblong-lanceolate, ending in a smooth, yellow awn -- Phascum
16a Calyptra covering 1/4-1/2 of the capsule, more than 0.2 mm in overall length; capsule cleistocarpous; leaves costate or ecostate -- Ephemerum
16b Calyptra minute, less than 0.2 mm in length, covering only the tip of the capsule; capsule dehiscing near the middle; leaves ecostate -- Micromitrium
17a (l0b) Plants minute, almost stemless; ephemeral; capsules immersed; growing on soil -- 18
17b Plants minute to large; capsules immersed to exserted; if plants minute with immersed capsules, growing on rocks, trees or soil and not ephemeral -- 20
18a Outer cells of capsule wall (exothecial) very lax and thin walled -- Physcomitrella
18b Exothecial cells of capsule wall evenly thickened or thickened at the corners -- 19
19a Capsules dehiscing at the middle; exothecial cells thickened at the corners -- Aphanorrhegma
19b Capsules with a distinct operculum; exothecial cells not thickened at the corners -- Physcomitrium
20a (17b) Leaves with filiform green photosynthetic outgrowths on the upper surface or with lamina-like vertical lamellae on the upper surface, at least on the costa -- 21
20b Leaves without such outgrowths; sometimes with deciduous gemmae -- 28
21a Leaves with filiform green photosynthetic outgrowths on the upper surface -- 22
21b Leaves with vertical lamellae on the upper surface -- 23
22a Filaments from the midrib only -- Crossidium
22b Filaments from the upper surface of the leaf -- Aloina
23a Leaves entire, oval, thin, with lamellae on distal half of costa; costa prolonged into a hair (awn) -- Pterigoneurum
23b Leaves toothed on the margin or with translucent sides folded up over the upper surface; peristome teeth 32-64, with tips attached to a transverse membrane -- 24
24a Lamellae on the upper surface of the leaf 1-20, calyptra smooth or with only a few hairs -- 25
24b Lamellae on the upper surface of the leaf more than 20; calyptra hairy -- 27
25a Cilia borne on the upper part of the leaf sheath; lamina of leaf bistratose -- Bartramiopsis
25b Cilia absent; lamina unistratose or bistratose along the margin -- 26
26a Margin of leaf bordered with long narrow cells -- Atrichum
26b Leaves not bordered; often with lamellae on the back -- Oligotrichum
27a (24b) Capsule cylindrical; calyptra densely hairy; leaves serrate at least in the upper half; marginal cells of lamellae papillose, or if smooth, then the leaves thin and strongly crisped when dry -- Pogonatum
27a Capsule 4-6 angled; calyptra slightly to densely hairy; leaves entire to serrate, never thin and crisp ate when dry; marginal cells of lamellae never papillose -- Polytrichum
28a Plants growing on rich organic soil, dung, bones, or other organic matter of animal origin; peristome teeth 2 or 3 cells thick, the outer cells quadrate; teeth forming 32 curly threads, or 16 teeth 2 cells wide, or 8 teeth 4 cells wide, often strongly reflexed when dry, or capsules cleistocarpous and peristome absent; hypophysis (lower part of capsule) well developed in operculate species and often larger than the urn -- 29
28b Plants not having the above combination of characters; peristome when present single or double, composed of teeth formed by strips of cell-wall split apart through the cell cavities; growing on various substrates but not restricted to rich organic soil, bones, or other organic matter -- 33
29a Capsule cleistocarpous, without peristome or hypophysis; growing on peaty soil of arctic-alpine regions of Alberta, Alaska, and Colorado -- Voitia
29b Capsule with operculum and hypophysis -- 30
30a Leaves ovate to ovate-spatulate, the apex broad and rounded; basal cells with long cilia on the margins; peristome wanting; on soil in rock crevices in the mountains of Washington and Alaska -- Oedipodium
30b Leaves without the above combination of characters -- 31
31a Hypothesis of capsule not wider than the urn and lighter in color -- Tayloria
31b Hypothesis of capsule wider than urn when moist -- 32
32a Hypothesis distinctly wider than the urn, fresh or dry, usually darker in color; columella exserted; teeth of peristome 3-layered -- Splachnum
32b Hypothesis when fresh and moist only slightly wider than urn, not conspicuously colored; columella not exserted -- Tetraplodon
33a (28b) Stems erect, unbranched, or with branches erect, generally in tufts; archegonia and sporophytes terminal (may appear lateral because of innovative branches arising below the sporophytes) Acrocarps -- 34
33b Stems creeping or ascending, usually extensive branched, in interwoven mats; archegonia, antheridia, and sporophytes lateral or at the ends of branches Pleurocarps -- 139
34a Leaves lanceolate to spatulate with sheathing bases that have a conspicuous area of large, inflated, hyaline cells next to the costa and with marginal or intra-marginal border of elongated hyaline cells or with a thickened border -- 35
34b Leaves, especially the bases, not as above -- 36
35a Leaves with intramarginal border of hyaline or yellowish elongated cells -- Calymperes
35b Leaves without intramarginal border of elongated cells; border marginal, composed of elongated hyaline cells or of thickened, double wing-like green cells -- Syrrhopodon
36a (34b) Leaf cells conspicuously bulging or bulging mammillose, at least on the up-per (ventral) side, or papillose with papillae not, or scarcely, including the cell cavity, or roughened by fine longitudinal ridges (striolate) -- 37
36b Leaf cells smooth -- 83
37a Leaf cells conspicuously bulging mammillose, at least on upper surface -- 38
37b Leaf cells papillose or striolate -- 43
38a Leaf cells mammillose on upper side; smooth or slightly papillose on lower side -- 39
38b Leaves mammillose on both sides -- 41
39a Leaves 2 cells thick, the upper (ventral) cells mammillose, the lower (dorsal) cells smooth -- Timmiella
39b Leaf cells mainly in one layer -- 40
40a Leaves broadly lanceolate from a broader base; calyptra often adhering to the tip of seta after falling from the mature capsule -- Timmia
40b Leaves broadly oblong-ovate, apex obtuse, slightly apiculate; brood bodies (gemmae) often borne on axillary filaments -- Hyophila
41a (38b) Plants very small; leaves narrow, slenderly lingulate (tongue shaped), apex rounded, costa near the apex obscured by bulging cells -- Luisierella
41b Plants not as above -- 42
42a Leafy shoots 3-5 mm tall, from creeping stems; leaves entire; growing on trees in the southeastern United States -- Groutiella
42b Leafy shoots 1-10 cm tall, not growing from creeping stems; leaves nearly entire to finely serrate or coarsely serrate; growing mainly on rocks, not on trees -- Dichodontium
43a (37b) Cells at basal angles (alar cells) of leaves enlarged and clearly differentiated, cell walls colored brown or hyaline -- 44
43b Alar cells not enlarged and clearly differentiated -- 45
44a Leaf cells longitudinally striate; perichaetial leaves truncate or short pointed; capsules erect and symmetric -- Dicranoweisia
44b Leaf cells papillose; perichaetial leaves subulate; capsules inclined to suberect, usually distinctly asymmetric -- Dicranum
45a (43b) Stems repeatedly branching, appearing more or less pleurocarpous; sporophytes borne at intervals -- 46
45b Stems strictly upright, sparsely branched; sporophytes terminal -- 54
46a Cells of leaf narrow with extremely wavy walls; leaves lanceolate, ending in a serrate, white hair, or hair obsolete -- Racomitrium
46b Cells wall not wavy -- 47
47a Leaves without a costa, colorless at apex, often awned -- 48
47b Leaves with costa, lanceolate to ovate lanceolate; capsules with broad peristome teeth; tufted blackish mosses growing on trees or rocks -- 50
48a Papillae forked; seta shorter than leaves -- Hedwigia
48b Papillae simple; seta longer than leaves -- 49
49a Leaves acuminate, ending in an elongate, hyaline, flexuous apex; capsule sulcate when dry -- Pseudobraunia
49b Leaves muticous (without a hyaline point); capsule smooth when dry -- Braunia
50a (47b) Leaves not crisped and contorted when dry -- Orthotrichum
50b Leaves crisped and contorted when dry -- 51
51a Calyptra cucullate, never hairy; peristome absent -- 52
51b Calyptra campanulate, glabrous or hairy -- 53
52a Costa with central guide cells, or the leaves toothed; gemmae absent; growing on rocks and trees -- Amphidium
52b Costa without guide cells or the guide cells ventral; gemmae common; growing on trees and rocks -- Zygodon
53a (51b) Calyptra smooth or with few hairs; stomata immersed in capsule wall; basal marginal cells not particularly differentiated; gemmae absent -- Orthotrichum
53b Calyptra hairy; stomata superficial; basal cells differentiated, very thick walled, yellow, arranged in rows fanning out from the costa; sterile plants usually with septate gemmae on the leaf tips -- Ulota
54a (45b) Plants in small, cushion-like tufts; setae often very short; capsules immersed to short exserted; growing on rocks and trees -- 50
54b Plants usually in more extensive tufts; usually setae longer and capsule long exserted; normally growing on rocks or soil -- 55
55a Leaves contracting from an ovate, clasping base into a narrow subulate awn roughened by papillae formed by projecting cell ends -- Trichodon
55b Leaves not as above -- 56
56a Leaves broad, widest at middle or above; costa with dorsal stereids or none, often ending in an awn; cells of lower 1/4 of leaf colorless -- 57
56b Leaves lanceolate to linear-lanceolate, widest below the middle, long tapering to the apex; cells of lower 1/4 of leaf various -- 64
57a Leaves opaque in upper half with densely crowded coarse rounded papillae; lower leaf cells transparent, large, with thick transverse walls (usually brown); calyptra cylindrical, beaked, persistent, covering the capsule -- Encalypta
57b Papillae dot-like or columnar or c-shaped, o-shaped, or forked; clear cells at base thin walled; calyptra smaller, split on one side and deciduous -- 58
58a Margins of leaf thicker than median part due to deeper cells or more than one layer, or margins composed of greatly elongated cells -- 59
58b Margins of leaf not differentiated as above -- 60
59a Border of leaf composed of deep cells or more than one layer of cells -- Scopelophila
59b Border of leaf composed of greatly elongated cells -- Tortula
60a (58b) Plants with leaves very much broken, the fragments serving as gemmae -- Tortula
60b Plants with leaves not broken into fragments -- 61
61a Plants with gemmae -- 62
61b Plants without gemmae -- 63
62a Gemmae club-shaped, in axils of leaves -- Barbula
62b Gemmae resembling small serrate leaves or occurring on borne or the surface of the leaf -- Tortula
63a (61b) Peristome absent or composed of 16 teeth, slender and acute, split and broken off -- Desmatodon
63b Peristome of 32 spirally twisted thread from a basal membrane, colorless cells at base of leaf extending up along the costa -- Tortula
64a (56b) Margins of leaves distinctly involute -- 65
64b Margins of leaves revolute or plane -- 66
65a Peristome present, inserted at the mouth of the capsule; costa 60µ or more wide at the base; leaves linear-lanceolate from a broadly oblong to oblong-lanceolate base -- Trichostomum
65b Peristome absent; if present, inserted below the mouth of the capsule; costa 50µ or less wide at base, or if wider, then leaves narrowly oblong-lanceolate -- Weissia
66a (64b) Stems matted together with brown, branching rhizoids -- 67
66b Stems free and separate -- 72
67a Many stems ending in a naked stalk bearing a cluster of gemmae; cells isodiametric with a single large papillae near the middle of the cell; capsule cylindrical, curved and ribbed -- Aulacomnium
67b Without gemmae; papillae much smaller -- 68
68a With one low papillae over the cell cavity; capsule inclined, curved, cylindric; peristome of 16 red, forked teeth -- Cynodontium
68b With papillae at one or both ends of the cell; capsule globose to ovoid, inclined to erect, wrinkled to often longitudinally ribbed when dry -- 69
69a Plants of wet, seepy placed; leaves lanceolate to ovate-lanceolate, capsule ribbed and furrowed -- Philonotis
69b Plants of drier habitats as shaded rocks or banks; leaves linear, narrowly-lanceolate to acicular, at least in the upper half -- 70
70a Leaves 4-7 mm long, curly or straight; capsule ribbed and furrowed when dry -- Bartramia
70b Leaves 0.8-3.5 mm long, erect, appressed; capsule smooth to furrowed when dry -- 71
7la Stems with conspicuous clusters of reddish brown rhizoids; leaves 2.5-5.0 mm long; capsule erect, smooth to somewhat wrinkled but never strongly ribbed when dry, operculum conic -- Anacolia
7lb Stems with less conspicuous clusters of rhizoids; leaves small, to 1.5 mm long, stiff; capsule inclined, operculum beaked -- Conostomum
72a (66b) Margins of leaf revolute -- 73
72b Margins plane, at least in upper half -- 78
73a Costa with a single stereid band -- 74
73b Costa with two stereid bands -- 75
74a Leaves linear-lingulate; costa ending below the apex, spurred above -- Husnotiella
74b Leaves ovate to oblong-lanceolate, costa excurrent, not spurred above -- Phascum
75a (73b) Leaf margins 2-3 cells thick -- Didymodon
75b Leaf margins 1-cell thick -- 76
76a Peristome of 32 spirally twisted, papillose threads, or entirely absent -- Barbula
76b Peristome of 16 erect, slenderly triangular teeth, cleft or perforated -- 77
77 a Leaves entire throughout -- Didymodon
77b Leaves denticulate to strongly denticulate at apex; plants usually brick-red below -- Bryoerythrophyllum
78a (72b) Colorless cells at base of leaf extending up along the margin -- 79
78b Cells of leaf base not as above -- 80
79a Hyaline cells of leaf base not reaching the costa; leaves serrate above -- Pleurochaete
79b Hyaline cells of leaf base reaching the costa; leaves entire -- Tortella
80a (78b) Leaves toothed on the margin where the colorless cells meet the green ones -- Eucladium
80b Leaves with entire or wavy margins -- 81
81a Leaves slenderly tapering to apex, to 4 mm long; peristome teeth short, irregular -- Trichostomum
81b Leaves acute to obtuse, smaller, to 1.5 mm -- 82
82a Leaves bistratose in patches; archegonial inflorescences lateral -- Anoectangium
82b Leaves not bistratose; archegonial inflorescences terminal -- Gymnostomum
83a (36b) Plants growing on bark of trees in long creeping stems with crowded, erect (2-8 mm) densely leafy branches on which sporophytes are borne -- 84
83b Plant growing on soil, rocks, or trees but not forming long creeping stems with erect, branches densely leafy -- 85
84a Cells near base of leaf small, rounded; capsule ovoid-globose; widespread in the eastern United States -- Drummondia
84b Cells near base of leaf linear; capsule oblong-cylindric; southeastern coastal plain -- Scholtheimia
85a (83b) Very small mosses, less than 4 mm tall; extremely difficult to identify without capsules -- 86
85b Larger mosses, stems usually 4 mm or more tall, if minute, with persistent protonema -- 91
86a Capsules immersed in or barely emergent from the upper leaves; seta short; peristome absent -- 87
86b Seta longer; capsule not immersed in or barely emergent from the upper leaves -- 89
87a Spores very large, 100-300µ in diameter, 4-60 in a spherical capsule; calyptra very small -- Archidium
87b Spores smaller, 20-70µ in diameter -- 88
88a Spores 45-70µ in diameter; calyptra 4-angled, completely covering the capsule -- Pyramidula
88b Spores smaller, 20-40µ in diameter; calyptra smaller, not 4-angled or covering the capsule at maturity -- 10
89a (86b) Plants dark green in color, minute (1-2 mm tall), growing as velvety films on limestone rocks; peristome teeth not split (or lacking) -- Seligeria
89b Plants green to yellow-green in color, larger, usually growing on soil or on rocks; peristome teeth split half way down or divided into threads -- 90
90a Teeth divided into threads -- Ditrichum
90b Teeth split half way down -- Dicranella
91a (85b) Leaves distinctly in three ranks; stems triangular with outer cells thin-walled and colorless; capsules globular; peristome double -- Plagiopus
91b Leaves in 5 ranks; stems not as above -- 92
92a Leaves 6-20 times as long as broad, mostly long-tapering to a slender upper half -- 93
92b Leaves 1-5 times as long as broad -- 111
93a Cells at basal angles of leaf (alar) enlarged, often with brown walls, or if not clearly differentiated, leaves with a clasping base or with multicellular gemmae on underside of leaf near base -- 94
93b Alar cells not notably enlarged -- 103
94a Peristome teeth undivided; capsule cylindrical, erect, 1.5-2 mm long; leaves strong crisped, (curly) when dry -- Dicranoweisia
94b Peristome teeth split at the tip, split half way down, or undivided; if undivided capsule pear-shaped, erect, about 1 mm long and leaves erect or bent to one side when dry -- 95
95a Peristome teeth undivided or split just at the tip -- Blindia
95b Peristome teeth split half way down -- 96
96a Costa narrow, 1/3-1/10 of leaf at base -- 97
96b Costa without stereid bands or guide cells, very wide -- 102
97a Leaves very brittle, mostly broken off; costa without stereids -- Dicranum
97b Leaves not easily broken; costa with or without stereids -- 98
98a Costa without stereids; leaves crisped when dry -- Kiaeria
98b Costa with stereids -- 99
99a Base of leaf broad, clasping, abruptly narrowed to the slender upper portion; capsule strumose -- Oncophorus
99b Leaves evenly tapering from base upward; capsules not strumose -- Dicranum
100a (96b) Costa with stereid bands -- 101
100b Costa wide, 1/3-7/8 of leaf at base -- 100
101a Costa with dorsal and ventral stereid bands, with guide cells in between; surface cells large and similar on both sides -- Dicranodontium
101b Costa with large clear cells ventrally; dorsally with strands of stereids alternating with large clear cells -- Campylopus
102a (100b) Plants with clusters of fusiform gemmae whose surface cells are clear and empty -- Brothera
102b Plants without gemmae; costa of 3 or 4 layers of uniform cells -- Paraleucobryum
103a (93b) Leaf cells long-rhomboidal to linear, 6-12 times as long as wide; capsules inclined to nodding, pyriform or oblong-pyriform -- 104
103b Leaf cells shorter; capsules erect or inclined, not pyriform -- 105
104a Leaves linear-subulate; costa filling about 1/2 of the base and most of the slender tip -- Leptobryum
104b Leaves oblong-lanceolate; costa narrow -- Pohlia
105a (103b) Plants restricted to wet seepage areas in Florida, Georgia, and Louisiana; leaves narrowly linear-lanceolate, widely spreading when moist, giving plants a feathery appearance, costa narrow, percurrent; margins of leaves without elongated cells but with paired teeth from base to apex; peristome double -- Rhizogonium
105b Plants not possessing the above combination of characters -- 106
106a Neck of capsule about as long as urn -- Trematodon
106b Without a noticeable neck -- 107
107a Teeth 16, split half way down or to base into threads -- 108
107b Teeth 16, not split at all; leaves 2-3 mm long erect, not filiform; margins plane -- Rhabdoweisia
108a Teeth split to base or nearly so -- 109
108b Teeth split to the middle -- Dicranella
109a Leaves narrowly lanceolate to subulate; gins neither revolute throughout nor toothed near the apex -- Ditrichum
109b Leaves lanceolate or ovate-lanceolate, margins nearly revolute throughout and irregularly toothed near apex 110
110a Plants bluish or glaucous -- Saelania
110b Plants dark-green to red-brown -- Ceratodon
111a (92b) Leaves dense and blackish, never broadly spatulate to lingulate; upper cells mostly isodiametric, small and thick-walled, peristome single or lacking -- 112
111b Leaves bright or dark green -- 115
112a Walls of leaf cells closely and evenly wavy; peristome teeth 16, split nearly to base into 2 or 3 slender prongs -- Racomitrium
112b Walls smooth or irregularly wavy at the middle of leaf -- 113
113a Leaves bearing rhizoids at base; seta shorter than leaves; on rocks in streams; western United States and Alaska -- Scouleria
113b Leaves without rhizoids -- 114
114a Leaves crisped when dry, linear from a lanceolate base; margins plane, entire, or serrate above; apices obtuse to almost blunt; calyptra nearly covering capsule, split into several linear strips -- Ptychomitrium
114b Leaves usually imbricate when dry, ovate to linear-lanceolate, margins plane to narrowly or strongly recurved; apices muticous to ending in a colorless hair point; calyptra various -- Grimmia
115a (111b) Upper leaf cells elongate rectangular, rhombic-hexagonal, to linear, 6-12:1 -- 116
115b Upper leaf cells quadrate, hexagonal, rhombic, or short-rectangular, 6 times or less as long as wide -- 118
116a Leaves bordered by elongate, often reddish cells; leaves of sterile stems more or less dimorphous, smaller in the dorsal row and the larger more or less distichous -- Epipterygium
116b Leaves not as above -- 117
117a Sporophytes arising from a short basal shoot over-topped by a long innovation; peristome delicate and single -- Mielichhoferia
117b Sporophytes terminal; peristome double and well developed -- Pohlia
118a (115b) Upper leaf cells quadrate, small (to 15µ in diameter) -- 119
118b Upper leaf cells hexagonal, rhombic or short-rectangular, larger (to 800µ long) -- 125
119a Margins of the leaves revolute -- 120
119b Margins of leaf plane (occasionally slightly revolute near base) -- 121
120a Leaves entire -- Didymodon
120b Leaves toothed at the apex -- Ceratodon
121a (119b) Leaves entire -- 122
121b Leaves toothed at apex -- Aulacomnium
122a Leaves half sheathing at base, sharply bent back (squarrose) at middle -- Dicranella
122b Leaves erect, not sheathing or squarrose -- 123
123a Leaves oblong-spatulate, rounded at apex; marginal cells somewhat thick-walled forming a distinct border; usually growing on copper bearing rocks -- Scopelophila
123b Leaves not as above -- 124
124a Leaves narrowly lance-acuminate, slenderly acute; capsules minute (0.5 mm), horizontal, and black -- Catoscopium
124b Leaves lanceolate, ovate-lanceolate, oblong-lanceolate to obovate, ending in an apiculus or awn; capsules minute to small (0.5-1.5 mm), orange to red-brown -- Pottia
125a (118b) Marginal cells similar to those of lamina -- 132
125b Marginal cells slender, fusiform, not similar to cells of lamina -- 126
126a Capsules erect; peristome single, composed of 32 teeth -- 127
126b Capsules nodding to erect; peristome double, composed of 16 teeth made of cell walls only split apart through the cavity; inner peristome sometimes absent -- 128
127a Leaves oval-oblong or oblong-lanceolate, margins serrate; costa bearing a few short obsolete lamellae; peristome composed of 32 stout teeth attached to a transverse membrane, each tooth made up of many cells -- Atrichum
127b Leaves oblong or oblong-obovate; margins entire; costa without lamellae; peristome composed of 32 spirally twisted teeth -- Tortula
128a (126b) Leaves to 6 mm long, in dense terminal rosettes; stems connected by a tough underground "rhizomes" -- Rhodobryum
128b Leaves not both large and in dense terminal rosettes; stems not connected by underground "rhizomes" -- 129
129a Upper leaf cells prosenchymatous, rhomboidal, rhomboid-hexagonal to linear; capsules nodding to erect, pear-shaped (broadest near mouth) -- 130
129b Upper leaf cells parenchymatous, mostly hexagonal to rounded; capsules nodding, barrel-shaped, narrowed equally at both ends -- 131
130a Upper leaf cells rhomboidal-hexagonal, 2-5 times as long as wide; capsule inclined to pendant -- Bryum
130b Upper leaf cells short-rhomboidal, 1-2 times as long as broad; capsule erect -- Brachymenium
131a (129b) Margins of leaf entire, abruptly cuspidate; outer peristome shorter than the inner -- Cinclidium
131b Margins serrate or if entire leaves not abruptly ending in a long, cuspidate point; outer peristome as long as the inner -- Mnium
132a (125a) Upper leaf cells with pointed ends -- 133
132b Upper leaf cells with flat, transverse ends -- 134
133a Plants dendroid, large, to 8 mm tall -- Leucolepis
133b Plants not dendroid, smaller, to 5 cm tall though usually smaller -- Mnium
134a (132b) Capsules with neck nearly as long as urn, nearly erect; peristome double, the inner peristome taller -- 135
134b Neck of capsule not noticeable; outer peristome stronger than inner, or peristome single or absent -- 136
135a Leaf cells large arid thin-walled, 20-40µ wide; plants soft and delicate -- Amblyodon
135b Leaf cells small, 15µ or less wide; plants coarse, more rigid -- Meesia
136a (134b) Capsule unsymmetric, horizontal; peristome of 16 teeth, each one split from base nearly or quite to apex; costa wanting or weak, not extending to apex; plants very small with persistent green protonema -- Discelium
136b Capsules erect or nodding, symmetric or asymmetric; peristome absent, single, or double; leaves with a distinct costa from base to apex or occasionally excurrent -- 137
137a Capsule unsymmetrical (arcuate); peristome double -- Funaria
137b Capsule erect, symmetrical -- 138
138a Peristome absent; calyptra mitrate -- Physcomitrium
138b Peristome single, often rudimentary; calyptra cucullate -- Entosthodon
139a (33b) Leaves papillose, at least on the dorsal (lower) side and on the upper half of the leaf -- 140
139b Leaves smooth; more or less glossy -- 174
140a Papillae formed by projecting angles of cell wall -- 141
140b Papillae located over the cell-cavity; if located at the end of the cell not formed by a projecting angle -- 150
141a Costa of leaves single, extending to the middle of the leaf or beyond -- 142
141b Costa of the leaves absent, short and double or if extending beyond the middle of the leaf, double -- 144
142a Leaves large, to 3-5 mm long, rugose and plicate, secund -- Rhytidium
142b Leaves small, to 1.2 mm long, not rugose or plicate -- 143
143a Leaves sharply serrate, translucent, decurrent; costa not prominent; cells fusiform, 1:4-6, thin-walled; on soil -- Bryhnia
143b Leaves entire or nearly so, mostly revolute on margin, opaque, not decurrent; costa prominent on back of leaf; cells small, angular, rather thick walled; paraphyllia numerous; on rocks -- Pseudoleskea
144a (141b) Paraphyllia lacking -- 145
144b Paraphyllia few and small to abundant and large -- 148
145a Plants small, creeping, forming mats; leaves 1.5-2.5 mm long -- 146
145b Plants large, erect and spreading, to 15 cm tall; leaves long, cordate-triangular, widely spreading, wet or dry; costa double reaching the middle of the leaf or beyond; upper cells spinose-papillose on back -- Rhytidiadelphus
146a Leaves broadly cordate at base, abruptly long-acuminate, strongly falcate-secund -- Ctenidium
146b Leaves ovate to ovate-lanceolate; acuminate to abruptly acuminate, not broadly cordate at base or strongly falcate-secund -- 147
147a Stem leaves distant, spreading, ovate-lanceolate, abruptly acuminate; upper leaf cells about 8.1, fusiform; southern Georgia and Florida -- Mittenothamnium
147b Stem leaves close, julaceous imbricate when dry, ovate, acuminate; upper leaf cells 3-4:1, irregularly rhomboidal to oblong; British Columbia to California -- Pterogonium
148a (144b) Plants small and slender, sparsely and irregularly branched; leaves small, to 0.6 mm long; paraphyllia few, small, filiform or branched -- Pterigynandrum
148b Plants larger, not slender, stems to 20 cm long; paraphyllia large and abundant -- 149
149a Leaves rugose (transversely wrinkled), plicate, falcate-secund, irregularly branched; Pacific northwest -- Rhytidiopsis
149b Leaves not rugose or falcate; shoots 2-3 times pinnately branched in one plane, each year's growth arising from the middle of the preceding -- Hylocomium
150a (140b) Plants with creeping, leafless stems and secondary stems erect, fernlike or dendroid -- 151
150b Plants not conspicuously fern-like or dendroid -- 152
151a On hardwood trees in Florida and Louisiana -- Pireella
151b On trees and rocks, western United States -- Dendroalsia
152a (150b) Leaves oval, rounded at apex, flattened with two rows of dorsal leaves and much smaller ventral leaves -- Erpodium
152b Leaves not as above -- 153
153a Leaves without a costa or with a short or long double costa -- 154
153b Leaves with a single costa reaching the middle of the leaf or beyond in at least some leaves -- 159
154a Costa long and double -- Callicostella
154b Costa short and double to absent -- 155
155a Median leaf cells linear-flexuose, 10-12:1, with a single row of minute papillae down the middle of the dorsal side; Florida -- Taxithelium
155b Median leaf cells oval to short-rhomboidal, 1-8:1, papillae not in a single row or dorsal side -- 156
156a Paraphyllia present, linear or lanceolate, not branched, few and small -- Heterocladium
156b Paraphyllia absent -- 157
157a Leaves ovate or narrower, acuminate to ovate-lanceolate; margins entire to serrulate; plants light olive- or yellow-green -- 158
157b Leaves round-ovate, deeply concave, margins spinose-dentate from base to apex; plants glaucous-green -- Myurella
158a Leaf margins serrulate from base to apex; median leaf cells 1-2:1, unipapillose; costa absent; widespread in the eastern United States -- Schwetschkeopsis
158b Leaf margins slightly toothed at apex; median leaf cells 8:1, with 1 or 2 low papillae; costa absent or slender and single, ending about mid-leaf; Florida -- Leucodontopsis
159a (153b) Plants complanate (stems flattened parallel to the substratum) -- Stereophyllum
159b Plants not complanate -- 160
160a Plants with numerous capsules immersed in perichaetial leaves; costa protruding on dorsal side of leaf; leaf cells narrowly oval or elliptical with very thick walls; quadrate alar cells numerous; on trees -- Cryphaea
160b Capsule when present exserted beyond the perichaetial leaves; costa and leaf cells not as above -- 161
161a Median leaf cells with papillae forming a single row over the center of the cells; Florida and Louisiana -- 162
161b Papillae not forming a single row over the center of the cells -- 163
162a Leaves auriculate, decurrent; median leaf cells in rows oblique to the costa -- Papillaria
162b Leaves not auriculate or decurrent; median leaf cells paralleling the costa -- Barbella
163a (161b) Leaf cells with a single very large papilla, as tall as the diameter of the cell, often forked into 2, 3 or 4; shoots julaceous, leaves nearly circular, deeply concave; United States east of the Plains -- Thelia
163b Papillae smaller, often several on one cell -- 164
164a Paraphyllia absent or few, linear, scalelike or lanceolate -- 165
164b Paraphyllia numerous, filamentous, mostly branched -- 172
165a Leaves ending in a hair point -- 166
165b Leaves not ending in a hair point -- 168
166a Plants usually growing on trunks of trees as scattered strands; leaves squarrose when moist; cells unipapillose -- Lindbergia
166b Plants in dense mats on rocks and bases of trees, or on soil; uni-papillose or pluri-papillose -- 167
167a Leaves entire -- Anomodon
167b Leaves dentate-serrate; western United States -- Claopodium
168a (165b) Leaves clasping the stem at base -- 169
168b Leaves not clasping, mostly ovate, acute or obtuse, not at all complanate, closely appressed when dry, spreading when wet; peristome segments narrow, keeled -- 170
169a Medium to large matted or tangled mosses -- Anomodon
169b Mosses in small thin patches on bark; leaves much broken and appressed tightly against the stem when dry -- Haplohymenium
170a (168b) Leaves with costa variable, ending below the middle, short or double or both or absent; cells with low papillae or even smooth -- Pseudoleskeella
170b Leaves with a single costa usually extending beyond the middle of the leaf; cells papillose or smooth -- 171
171a Median cells of leaves isodiametric, papillose; peristome teeth sharply bent inward at the base when dry -- Leskea
171b Median cells longer than wide, oval-hexagonal, smooth or slightly papillose; teeth straight when dry -- Leskeella
172a (164b) Paraphyllia matted together on stem and present on base of leaf -- Helodium
172b Paraphyllia not attached to leaves -- 173
173a Apical cell of branch leaves crowned with 2-4 papillae -- Thuidium
173b Apical cell of branch leaves with one terminal papillae -- Haplocladium
174a (139b) Paraphyllia or multicellular propagula present in leaf axils numerous and conspicuous -- 175
174b Paraphyllia or multicellular propagula few or none, usually not seen, if numerous, then plants complanate -- 182
175a Plants with creeping stems, erect scaly stems, and cluster of spreading leafy branches; dendroid in habit except in semi-aquatic situations -- Climacium
175b Plants without a dendroid habit, if somewhat dendroid, growing on trees -- 176
176a Leaves strongly wrinkled (rugose), all bent toward one side of stem (secund), tips of branches hooked -- Rhytidiopsis
176b Leaves not both strongly rugose and secund -- 177
177a Plants with complanate-foliate branches ending in a slender flagella; paraphyllia lanceolate, serrulate; capsule longer than seta -- Metneckera
177b Plants not complanate-foliate -- 178
178a Costa single and strong, extending beyond the middle of the leaf -- 179
178b Costa absent, single or double, not extending much beyond the middle of the leaf when present -- 180
179a Costa very strong, ending in the tip (percurrent), or excurrent; alar cells large and clear -- Cratoneuron
179b Costa not quite percurrent; alar cells small, quadrate -- Pseudoleskea
180a (178b) Leaves revolute and strongly toothed in upper half -- Hylocomium
180b Leaves plane and entire to serrulate in upper half -- 181
181a Plants with slender creeping stems, naked or with a few scale-like leaves; secondary stems few, uncrowded, erect and simple; Florida -- Jaiegerina
181b Plants in mats, creeping stems not as above; secondary stems more numerous, ascending, sometimes flagelliform; British Columbia to California -- Alsia
182a (174b) Costa double, ending well beyond the middle of the leaf; leaf cells thin-walled, pellucid, hexagonal; Florida -- Cyclodictyon
182b Costa single and strong to short and/or double to absent -- 183
183a Costa strong with one or two short accessory ribs on each side at base of leaf -- Antitrichia
183b Costa single, reaching the middle of the leaf or beyond to lacking, or short and/or double -- 184
184a Costa single, reaching the middle of the leaf or beyond -- 185
184b Costa lacking, or short and/or double -- 230
185a Plants aquatic, normally completely submerged, at least sometime of the year -- 186
185b Terrestrial, on dry or wet substrates, not normally submerged -- 192
186a Leaves complanate (lying in two opposite rows) or more or less falcate-secund -- 187
186b Leaves not complanate or falcate-secund but appressed or erect or spreading -- 189
187a Leaves complanate -- Leptodictyum
187b Leaves more or less falcate-secund; shoots hooked at tip -- 188
188a Leaves 3-ranked, sharply keeled (folded along the costa) -- Dichelyma
188b Leaves not keeled, flat or tubulose, smooth or plicate -- Drepanocladus
189a (186b) Leaves 3-ranked, sharply keeled (folded along the costa), lanceolate -- Brachelyma
189b Leaves flat or concave, not keeled -- 190
190a Leaves finely serrate all round, broadly ovate to orbicular -- Eurhynchium
190b Leaves entire, flat or concave -- 191
191a Leaves thin, cordate-ovate to rounded orbicular, costa strong, usually ending below the apex; alar cells inflated and usually forming a well-marked area -- Calliergon
191b Leaves thick, opaque, lanceolate to ovate; costa very stout, excurrent -- Hygroamblystegium
192a (185b) Plants with horizontal "rhizome", erect wiry stems and many leafy branches (dendroid) -- Thamnobryum
192b Plants not dendroid -- 193
193a Leaves distinctly bordered with elongated, thick-walled cells in 2 layers; median cells rhomboid -- Sciaromium
193b Leaves not distinctly bordered -- 194
194a Leaves nearly circular, appressed, deeply concave, with abrupt slender tips; shoots fat and cylindric (julaceous) -- 195
194b Leaves narrowly lanceolate to ovate -- 196
195a Apex ending abruptly in a short twisted point -- Bryoandersonia
195b Apex ending in a long, narrow acumination, not twisted -- Cirriphyllum
196a (194b) Leaves narrowly lanceolate, long-tapering, falcate-secund to circinate -- Drepanocladus
196b Leaves ovate to lanceolate, rarely falcate, never circinate -- 197
197a Median leaf cells short, 1-5:1 -- 198
197b Median leaf cells elongated, 5-20:1 -- 214
198a Cell walls very thick, often irregularly so being thicker at the upper and lower ends of the cells -- 199
198b Cell walls thin, of equal thickness all round -- 205
199a Branches complanate -- 200
199b Branches not complanate -- 201
200a Leaves lingulate, truncate or notched at apex, or spathulate, asymmetrical, obtuse to rounded-obtuse -- 213
200b Leaves oblong-ovate, acuminate; leaves dimorphous -- Stereophyllum
201a (199b) Leaves entire near base, very shallowly denticulate above -- 202
201b Leaves sharply serrate above -- 203
201a Leaves 1.5-2 mm long; seta shorter than perichaetia leaves -- Forsstroemia
202b Leaves 0.5-0.7 mm long; seta 3-4 mm long, much longer than perichaetial leaves -- Clasmatodon
203a (201b) Leaves ovate, abruptly short-acuminate, margins plane and sharply serrate from base to apex; alar cells numerous and very small and thick-walled; Pacific slope only -- Isothecium
203b Leaves with tapering acumen, sharply serrate above -- 204
204a Teeth of leaf margin broad, ascending; southeastern United States -- Herpetineuron
204b Leaves revolute below, sharply serrate above with long, slender, reflexed teeth; Pacific coast only -- Antitrichia
205a (198b) Leaves distinctly serrate above the middle; seta rough -- 206
205b Leaves entire or slightly denticulate on lower half -- 207
206a Branch leaves 0.9 mm or less long, scarcely plicate; capsule horizontal -- Brachythecium
206b Branch leaves 1.3-2 mm long, strongly plicate; capsule nearly erect; western United States -- Homalothecium
207a (205b) Leaves squarrose-recurved, especially when wet -- Campylium
207b Leaves erect, spreading or appressed, not squarrose spreading -- 208
208a Leaves nearly at right angles to stem -- Leptodictyum
208b Leaves erect or appressed (imbricate) -- 209
209a Capsules erect; slender mosses on trees; leaves 0.8-1.5 mm long -- 210
209b Capsules curved, strongly contracted under the mouth when dry -- 211
210a Costa reaching the tip of leaf; cells small, 8-12µ in diameter, dense -- Leskeella
210b Costa weak, ending near the middle of leaf; cells 12µ wide, thin-walled, clear -- Anacamptodon
211a (209b) Costa very strong, extending to apex or beyond -- Hygroamblystegium
211b Costa strong or weak, ending below the apex -- 212
212a Margins entire -- Amblystegium
212b Margins serrulate -- Rhynchostegiella
213a (200a) Leaves truncate or notched at apex; Florida -- Neckeropsis
213b Leaves short-obtuse to rounded-obtuse -- Homalia
214a (197b) Shoots complanate-foliate -- 215
214b Shoots not complanate-foliate -- 216
215a Leaves entire, the base often obliquely attached to stem -- Leptodictyum
215b Leaves sharply serrate, the apex twisted; seta smooth -- Rhynchostegium
216a (214b) Alar cells thin-walled, clear, inflated -- 217
216b Alar cells little or not at all enlarged; leaves acute or acuminate, straight or nearly so, not recurved -- 221
217a Leaves entire, rounded at apex -- Calliergon
217b Leaves distinctly pointed at apex -- 218
218a Inflated alar cells broadly decurrent -- Brachythecium
218b Inflated alar cells clustered, not decurrent -- 219
219a Leaves acuminate -- 220
219b Leaves blunt or with short tips -- Hygrohypnum
220a Leaves slenderly acute, falcate-secund, at least at the hooked tips of the stem -- Drepanocladus
220b Leaves widely spreading with a very long acumination, entire; in very wet places -- Campylium
221a (216a) Leaves evenly tapering to a slender point, plicate -- 222
222b Leaves ovate to lanceolate, with curved outlines, not plicate or with only two longitudinal folds -- 223
222a Capsules oblong-cylindric, more or less curved; peristome perfect; large matted mosses, often yellowish -- Tomenthypnum
222b Capsules erect and symmetric; inner peristome imperfect, even the segments reduced -- Homalothecium
223a (221b) Alar cells little or not at all differentiated; beak of operculum as long as urn; plants generally glossy in appearance -- 224
223b Alar cells quadrate; beak conic or long-conic; plants not glossy -- 225
224a Apical cells of leaf short-rhomboidal to circular -- Eurhynchium
224b Apical cells not differentiated; seta smooth; robust pinnately branched plants; leaves clasping the stem -- Stokesiella
225a (223b) Leaves with a large area of thick- or thin-walled alar cells -- 226
225b Alar cells fewer, not occupying a large area at the base of the leaf; sometimes inflated -- 227
226a Alar cells thick-walled, rounded; cilia of peristome well-developed -- Isothecium
226b Alar cells thin-walled, quadrate, extending from margin to midrib; cilia of peristome lacking; capsules erect -- Brachythecium
227a (225b) Small glossy mats on trees; leaves about 1 mm long; serrate; leaves ovate to elliptical-oblong, abruptly acuminate; calyptra hairy; inner peristome adherent; eastern United States -- Homalotheciella
227b Plants larger, not possessing the above characteristics -- 228
228a Branches julaceous (cylindrical, densely and closely leafed); leaves smooth, concave; seta rough; western North America -- Scleropodium
228b Branches not julaceous; if sub-julaceous the leaves plicate -- 229
229a Leaves lanceolate, small quadrate alar numerous, not plicate, sharply serrate from base to apex -- Homalothecium
229b Leaves ovate or ovate-lanceolate, small alar cells not numerous; if leaves lanceolate or quadrate alar cells numerous, not sharply serrate from base to apex, smooth or plicate -- Brachythecium
230a (184b) Plants aquatic, long, and dangling, often in dense tufts; alar cells inflated -- Fontinalis
230b Plants terrestrial; xeric, mesic, or hydric, not in areas where subject to long periods of submergence in flowing water or if growing in water, costa short and double -- 231
231a Median leaf cells short, 2-5:1 -- 232
231b Median leaf cells long to very long, 5-20:1 -- 239
232a Cell walls very thick, the lumen elliptic to linear; alar cells very numerous -- 233
232b Cell walls thin, equally thick all around -- 234
233a Secondary stems little branched; calyptra smooth -- Leucodon
233b Secondary stems freely and often pinnately branched; calyptra hairy -- Forsstroemia
234a (232b) Leaves entire -- 237
234b Leaves finely denticulate to coarsely toothed -- 235
235a Leaves denticulate to very finely denticulate -- 236
235b Leaves coarsely toothed with whole projecting cells to serrate-dentate -- Fabronia
236a Branches not flattened -- Campylium
236b Branches flattened; Florida -- Vesicularia
237a (234a) Cells very large and clear, 50-60µ; alar cells not differentiated; plants of moist, wet, rock ledges -- Hookeria
237b Cells smaller, 7-8µ wide; alar cells small and numerous -- 238
238a Leaves minute, to 0.6 mm long -- Platydictya
238b Leaves larger, 0.8-1.2 mm long, concave -- Homomallium
239a (231b) Leaves with one inflated cell at extreme basal angle, and many quadrate cells; tips of shoots crowded with gemmae -- Platygyrium
239b Leaves not as above; gemmae if present, not forming clusters at the tips of shoots -- 240
240a Leaves with several (2 or more) distinctly inflated alar cells -- 241
240b Leaves with small quadrate alar cells or with little or no differentiation of alar cells or alar cells slightly inflated and hyaline -- 252
241a Alar cells in a transverse row of 3 or 4 inflated cells; operculum with a beak as long as urn -- Sematophyllum
241b Ajar cells in a cluster, inflated, 3 or 4 transversely and 3 or 4 up margin of leaf, or less inflated, thicker walled, often colored -- 242
242a Alar cells inflated, thin-walled, in a cluster, 3 or 4 transversely and 3 or 4 up margin -- 243
242b Alar cells more numerous, less inflated, thicker walled, often colored -- 244
243a Alar cells scarcely decurrent; leaves complanate and falcate-secund, sharply serrate on the slender acumination; capsules inclined smooth -- Brotherella
243b Alar cells decurrent; leaves squarrose, finely serrulate above; capsule longitudinally furrowed when dry -- Herzogiella
244a (242b) Leaves squarrose-recurved, long acuminate, entire -- Campylium
244b Leaves not as above -- 245
245a Leaves erect, straight, broad, blunt, sometimes more or less falcate -- 246
245b Leaves complanate -- 249
246a Leaves curved so that shoots are hooked at tips, rugose (wrinkled) when dry -- Scorpidium
246b Leaves not as above -- 247
247a Leaves ovate to orbicular, acute or abruptly short-acuminate, spreading, more or less falcate-secund -- Hygrohypnum
247b Leaves deeply concave, spoon-shaped, obtuse and rounded at apex, not falcate-secund -- 248
248a Tips of stems ending in a firm acute bud; alar cells much inflated, clear -- Calliergonella
248b Tips loose; stems red; alar cells somewhat inflated, usually colored and opaque -- Pleurozium
249a (245b) Leaves shiny, not falcate-secund; alar cells in a cluster, enlarged and clear -- 250
249b Leaves falcate-secund -- 251
250a Leaves entire -- Callicladium
250b Leaves serrate, especially on the slender acumen -- Heterophyllium
251a (249b) Plants rather large, handsome, distinctly pinnately branched to form triangular fronds; leaves strongly plicate -- Ptilium
251b Plants small to medium-sized, not particularly handsome in appearance, various branched, but not forming triangular fronds; leaves smooth to only slightly plicate -- Hypnum
252a (240b) Leaves with small quadrate alar cells -- 253
252b Leaves with little or no differentiation of alar cells, or alar cells slightly inflated and hyaline -- 260
253a Leaves appressed, broad and entire; shoots julaceous to slightly flattened; peristome teeth with few, long, smooth joints -- Entodon
253b Leaves spreading to loosely imbricate, complanate or falcate secund -- 254
254a Leaves spreading -- 255
254b Leaves complanate, falcate-secund, or loosely imbricate -- 256
255a Leaves slenderly acute, finely denticulate; stem leaves much larger than branch leaves -- Rhytidiadelphus
255b Leaves nearly orbicular, rounded and obtuse and denticulate at apex; cilia present in peristome -- Hygrohypnum
256a (245b) Leaves loosely imbricate and crowded; plants rather stout and robust, sparsely branched -- Scorpidium
256b Leaves complanate to falcate secund -- 257
257a Branches bent upward by reason of upwardly pointed leaves; cilia of peristome lacking -- Pylaisiella
257b Leaves curved downward or backward, or not curved and shoot very flat (complanate-foliate) 256
258a Shoots complanate-foliate -- Entodon
258b Shoots curved downward or backward -- 259
259a Shoots essentially cylindric, but the large leaves falcate -- Rhytidiadelphus
259b Shoots flat, the leaves both complanate and falcate -- Hypnum
260a (252b) Leaves imbricate to erect open -- 261
260b Leaves complanate-foliate or falcate-secund with branches hooked at tip -- 263
261a Stems and branches long, slender and stoloniferous at the ends and bearing small distant leaves -- Hygrohypnum
261b Stems and branches not as above -- 262
262a Leaves deeply plicate -- Orthothecium
262b Leaves not deeply plicate -- Plagiothecium
263a (260b) Leaves falcate-secund, the branches hooked at tips -- Rhytidiadelphus
263b Leaves complanate-foliate, not falcate -- 264
264a Leaves ovate to ovate-lanceolate; cells thin-walled, spindle-shaped -- 265
264b Leaves ovate to oblong; cells thick-walled, linear-flexuose -- Neckera
265a Leaves decurrent -- Plagiothecium
265b Leaves not decurrent -- 266
266a Pseudoparaphyllia present, leaf-like -- Taxiphyllum
266b Pseudoparaphyllia absent or if present, filamentous -- 267
267a Outer layer of stem cells large and thin-walled in cross section; leaves entire or minutely serrulate -- Isopterygiopsis
267b Outer layer of stem cells small and thick-walled in cross section; leaves serrulate to strongly serrate in upper half -- Isopterygium
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last update 2025-May-6