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Bryophyte Flora of North America

Key to the Moss Genera of North America North of Mexico

Dale H. Vitt and William R. Buck

Based on a key originally published in Contributions from the University of Michigan Herbarium 18: 43-71. 1992, which holds the copyright.

bryobar2.gif - 2151 Bytes

1. Gametophytes seemingly absent (consisting only of protonemata); sporophytes of asymmetric capsules and papillose setae.

Buxbaumia

1. Gametophytes present (with obvious leaves); sporophytes various.

2

2. Leaf cells arranged in a network of narrow, green cells alternating with large hyaline cells; branches usually in clusters.

Sphagnum

2. Leaf cells of one kind (green), or if of two kinds, branches never in clusters. 

3

3. Leaves attached in two rows on opposite sides of the stem (distichous).

4

3. Leaves attached all around the stem (foliate stems sometimes flattened [complanate]).

 7

4. Leaves appearing split at the base, consisting of two vaginant laminae which clasp the stem and base of the leaf above (equitant).

Fissidens

4. Leaves with expanded bases, not clasping leaf above.

5

5. Leaves ecostate; protonemata luminous.

Schistostega

5. Leaves unicostate; protonemata not luminous.

6

6. All leaves with a rough (papillose), linear subula.

Distichium

6. Vegetative leaves with a smooth mucro; perichaetial leaves with a smooth subula.

Bryoxiphium

7. Leaves with lamellae or filaments on the adaxial (upper) surface of the costa (excluding  propagula).

 8

7. Leaves without lamellae or filaments on the adaxial surface of the costa (but propagula sometimes present).

23

8. Leaves with filaments on the adaxial surface of the costa. 

 9

8. Leaves with lamellae on the adaxial surface of the costa.

10

9. Leaf margins broadly inrolled (and mostly obscuring the filaments).

Aloina

9. Leaf margins reflexed to revolute

Crossidium

10. Leaves bordered with elongate cells.

Atrichum

10. Leaves without elongate, marginal cells.

 11

11. Leaves ciliate at upper part of hyaline sheath.

Bartramiopsis

11. Leaves eciliate.

12

12. Upper leaf margins bistratose with paired, multicellular teeth; leaf apices with slender, smooth, caducous awns; restricted to the arctic.

Lyellia

12. Upper leaf margins unistratose with single teeth or entire; leaf apices muticous or with serrate awns. 

 13

13. Lamellae 2-4; leaves hyaline awned; plants small, less than 5 mm; peristome none or rudimentary and fragile. 

Pterygoneurum


13. Lamellae 4-50; leaves mostly not awned; plants mostly larger; peristome of 32 or 64 persistent teeth.

 14

14. Lamellae distinctly wavy.

15

14. Lamellae straight.

16

15. Upper leaf margins with border of hyaline, short- rhombic cells.

Psilopilum

15. Upper leaf margins not bordered.

Oligotrichum

16. Leaf laminae with teeth on abaxial (back) surface; calyptrae naked or with a few hairs.

Oligotrichum

16. Leaf laminae smooth at back; calyptrae densely hairy.

17

17. Plants with capsules.

18

17. Plants without capsules.

20

18. Capsules (2-)4(-6)-angled.

Polytrichum

18. Capsules cylindric.

19

19. Capsules without stomates; lumina of apical cells of lamellae not pyriform.

Pogonatum

19. Capsules with stomates; lumina of apical cells of lamellae pyriform.

Polytrichastrum

20. Apical cells of lamellae smooth or with faint cuticular ridges.

 21

20. Apical cells of lamellae papillose.

22

21. Plants small, less than 6 mm high; leaves never awned.

 Pogonatum

21. Plants larger; leaves with or without awns.

Polytrichum

22. Apical cells of lamellae rounded, quadrate or oblate.

Pogonatum

22. Apical cells elliptic-pyriform.

Polytrichastrum

23. Leaves deeply lobed with lobes linear-terete. 

Takakia


23. Leaves never lobed, flattened (although sometimes concave with margins inrolled or recurved).

24

24. Leaves without a costa or costa short and double, double, or single with 2-3 lateral spurs. 

25

24. Leaves with a single costa to at least midleaf.

114

25. Although appearing none, costa single and occupying entire leaf area, thus leaf appearing multistratose. 

26

25. Costa truly none or double; lamina always unistratose.

27

26. Leaves ligulate; green cells (chlorocysts) three- sided in section.

Octoblepharum

26. Leaves lanceolate; green cells four-sided in section.

Leucobryum

27. Upper leaf cells papillose or prorulose.

28


27. Upper leaf cells smooth (rarely with minute cuticular roughenings).

46

28. Leaf apices hyaline.

29

28. Leaf apices concolorous.

30

29. Leaf cells with a single, unbranched papillae (on each surface); capsules exserted, ribbed; perichaetial leaves entire; restricted to western North America.

Pseudobraunia

29. Leaf cells with 1-2 forked papilla (on each surface); capsules immersed, smooth; perichaetial leaves ciliate; widespread.

Hedwigia

30. Leaf cells pluripapillose.

31

30. Leaf cells unipapillose or prorulose.

33

31. Papillae arranged in rows over the lumina; leaf cells more than 5:1.

Taxithelium

31. Papillae randomly arranged over lumina; leaf cells less than 4:1.

32

32. Leaves obtuse; stems complanate-foliate.

Erpodium

32. Leaves short-acuminate; stems symmetrically foliate.

Braunia

33. Plants 2-3 pinnate, each year forming a flattened frond, the fronds arranged in a stair-step ascending pattern.

Hylocomium

33. Plants simple or 1-pinnate, not forming ascending fronds.

34

34. Leaves plicate. 

35

34. Leaves not plicate.

36

35. Costa double and extending to above midleaf; leaves spreading to squarrose.

Rhytidiadelphus

35. Costa short and double; leaves falcate-secund.

Ctenidium

36. Plants reddish-black, occurring tightly attached to rocks.

Andreaea

36. Plants greenish, occurring on various substrates.

 37

37. Plants minute, less than 2 mm, acrocarpous.

Ephemerum

37. Plants large, more than 1 cm, pleurocarpous.

38

38. Costa strong and double, extending to near leaf apex.

Callicostella

38. Costa short and double, ending below midleaf.

39

39. Alar cells numerous, oblate to rounded, strongly differentiated and extending up the margins; restricted to Pacific Northwest.

Pterogonium

39. Alar cells few, mostly quadrate, scarcely extending up the margins; widespread.

40

40. Cells at midleaf more than 5:1.

41

40. Cells at midleaf less than 5:1.

43

41. Apical leaf cells much shorter than those at midleaf.

Taxiphyllum

41. Apical leaf cells scarcely differentiated.

 42

42. Leaves slenderly acuminate; prorulose at both upper and lower ends of cells.

Chrysohypnum

42. Leaves acute; prorulose only at upper ends of cells.

Leptohymenium

43. Stem and branch leaves differentiated.

Heterocladium

43. Stem and branch leaves similar.

44

44. Leaves broadly ovate, concave, obtuse to obtuse- apiculate.

Myurella

44. Leaves lanceolate to ovate-lanceolate, acute to acuminate.

45

45. Leaves acute, serrulate only above; propagula often in leaf axils; northern in distribution.

Pterigynandrum

45. Leaves acuminate, serrulate throughout; propagula absent; eastern U.S. in distribution.

Schwetschkeopsis

46. Leaves ending in a hyaline awn.

47

46. Leaves concolorous at apex.

48

47. Leaf cells 2:1 or less, oblate-hexagonal throughout; eperistomate.

Erpodium

47. Leaf cells more than 3:1, upper cells short rhomboidal, basal cells quadrate; peristomate.

Venturiella

48. Plants aquatic, occurring submerged at least part of the year; leaves keeled or flat.

Fontinalis

48. Plants sometimes in wet habitats but never occurring submerged; leaves various but never keeled.

49

49. Plants acrocarpous, usually less than 4 cm.

50

49. Plants pleurocarpous, mostly larger.

53

50. Plants occurring on rock.

51

50. Plants occurring on bare soil.

 52

51. Plants reddish-black; capsules valvate.

Andreaea

51. Plants greenish-brown; capsules with four peristome teeth.

Tetrodontium

52. Protonemata abundant; capsules ovoid, apiculate; calyptrae campanulate-mitrate, deciduous.

Ephemerum

52. Protonemata sparse; capsules globose; calyptrae very small, persistent.

Micromitrium

53. Costa single with one or sometimes two supplementary costae on each side.

Antitrichia

53. Costa always double, or if single very short and without supplementary costae.

54

54. Costa long and double, extending to or beyond midleaf.

55

54. Costa short and double, usually ending just above leaf base.

59

55. Stems with numerous paraphyllia.

56

55. Stems lacking paraphyllia.

57

56. Stem leaves plicate, decurrent.

Hylocomiastrum

56. Stem leaves not plicate or decurrent.

Loeskeobryum

57. Leaf cells thin-walled, lax, abruptly bordered by elongate cells.

Cyclodictyon

57. Leaf cells firm-walled, not or only gradually bordered.

58

58. Plants forming mats; leaves falcate-secund at least at branch apices; exostome teeth striate, furrowed.

Trachyxiphium

58. Plants tufted; leaves somewhat contorted when dry but not falcate; exostome teeth papillose, not furrowed.

Lepidopilum

59. Leaves obtuse; plants small, rare, restricted to the mountains of southeastern U.S..

60

59. Leaves acute to acuminate, at least apiculate; plants mostly larger, widespread.

61

60. Leaves asymmetric with a basal lobe.

Homaliadelphus

60. Leaves symmetric without lobe.

Bryocrumia

61. Leaf cells lax, hexagonal.

62

61. Leaf cells firm- to thick-walled, rounded to linear.

63

62. Lateral and dorsal leaves differentiated in areolation; stems pinnately branched.

Vesicularia

62. Lateral and dorsal leaves with similar areolation; stems irregularly branched. 

Hookeria

63. Leaves slenderly long-decurrent.

 Plagiothecium

63. Leaves not at all decurrent to broadly auriculate.

64

64. Plants slender, thread-like; leaves mostly less than 1 mm long.

65

64. Plants larger; leaves more than 1 mm long.

67

65. Branch leaves more than 0.5 mm long.

Homomallium

65. Branch leaves less than 0.5 mm long.

66

66. Costa short and single; leaf cells rounded-elliptic.

Pseudoleskeella

66. Costa none or very short and double; leaf cells rhombic.

Platydictya

67. Leaves falcate-secund.

68

67. Leaves straight.

84

68. Upper leaf cells oblong-rhombic, ca. 3:1.

69

68. Leaf cells more or less linear, more than 6:1.

70

69. Alar cells numerous, oblate, extending up the margins in many rows.

Leucodon

69. Alar cells few, oblong-quadrate, in 1-2 rows along the insertion.

Sematophyllum

70. Plants regularly and closely pinnate, feather-like; fronds flat, erect to ascending, oblong-triangular.

Ptilium

70. Plants irregularly pinnate to unbranched, not feather-like; stems prostrate to loosely ascending. 

71

71. Mature branches erect and producing abundant and conspicuous propagula in their upper leaf axils. 

Platygyrium

71. Branches not producing propagula in leaf axils.

72

72. Branches curved-secund when dry, erect when moist; alar cells small and quadrate.

Pylaisiella

72. Branches little altered when dry; alar cells various.

73

73. Alar cells when differentiated quadrate, sometimes enlarged but not at all inflated.

74

73. Alar cells quadrate to oblong, inflated.

79

74. Stems with paraphyllia.

Rhytidiopsis

74. Stems without paraphyllia.

75

75. Plants very large (stem leaves 3.5-5.0 mm), stems ascending to erect; leaves plicate.

Rhytidiadelphus

75. Plants smaller (stem leaves less than 3.5 mm), stems prostrate to ascending; leaves various.

76

76. Alar cells none or very few; pale propagula often clustered in leaf axils.

Isopterygiopsis

76. Alar cells distinctly differentiated.

77

77. Plants occurring on wet rocks in mountain streams.

Hygrohypnum

77. Plants in various habitats but not as above.

78

78. Costa to ca. 1/3 the leaf length with the two forks not meeting at the base; plants of Alaska and Yukon.

Gollania

78. Costa mostly shorter, the forks joining at the base; plants widespread.

Hypnum

79. Plants occurring in calcareous fens or marl pools, dark reddish-brown; leaves obtuse.

Scorpidium

79. Plants occurring in other habitats, golden to green; leaves acute to acuminate.

80

80. Plants occurring on wet rocks in mountain streams.

Hygrohypnum

80. Plants in various habitats but not as above.

81

81. Alar cells thick-walled, inflated in several rows; leaf margins strongly serrate.

Heterophyllium

81. Alar cells inflated in 1(-2) rows, or if more, thin- walled; leaf margins entire to serrulate.

82

82. Stems surrounded by enlarged, thin-walled, hyaline cortical cells (hyalodermis); alar cells in large, subdecurrent areas.

Hypnum

82. Stems surrounded by small, thick-walled, concolorous cells; alar cells in 1(-2) rows.

83

83. Plants very shiny; leaves 0.8-1.4 mm long, densely serrulate above; capsules inclined, asymmetric. 

Brotherella

83. Plants slightly shiny; leaves 0.5-1.1 mm long, distantly serrulate above; capsule erect, symmetric.

Pylaisiadelpha

84. Stem leaves abruptly contracted to long setaceous point.

85

84. Stem leaves acute, acuminate or apiculate.

86

85. Leaf apices hyaline; alar cells scarcely differentiated.

Iwatsukiella

85. Leaf apices yellow; alar cells inflated and hyaline.

Wijkia

86. Leaves squarrose-recurved when dry, with channeled apices.

87

86. Leaves erect to spreading, or if squarrose only when moist, the apices mostly not channeled.

88

87. Stem leaves greater than 2.5 mm long; alar cells oblong, somewhat inflated, intramarginal.

Rhytidiadelphus

87. Stem leaves less than 2.5 mm long; alar cells subquadrate, not at all inflated, marginal.

Campylium

88. Plants occurring on wet rocks in mountain streams; leaves ovate, concave.

Hygrohypnum

88. Plants in other habitats but not as above; leaves various.

89

89. Stems complanate-foliate.

90

89. Stems symmetrically foliate.

96

90. Alar cells numerous and quadrate; capsules erect.

Entodon

90. Alar cells few, variously shaped; capsules usually inclined.

91

91. Plants occurring on vertical substrates, tree trunks or rocks.

Neckera

91. Plants occurring on horizontal substrates, rarely the extreme bases of trees.

92

92. Leaf margins serrulate throughout.

93

92. Leaf margins entire or serrulate only in upper half.

94

93. Apical leaf cells shorter than those at midleaf.

Taxiphyllum

93. Apical leaf cells undifferentiated.

Herzogiella

94. Rhizoids arising from leaf axils, papillose; leaf margins more or less entire.

Isopterygiopsis

94. Rhizoids arising from below leaf insertion, smooth; leaf margins serrulate above.

95

95. Pseudoparaphyllia filamentous; annuli not differentiated; plants mostly monoicous.

Isopterygium

95. Pseudoparaphyllia absent; annuli differentiated; plants mostly dioicous.

Pseudotaxiphyllum

96. Alar cells inflated.

97

96. Alar cells rectangular to quadrate, not inflated.

101

97. Plants erect; stems with hyalodermis; alar cells hyaline and in auricles.

Calliergonella

97. Plants prostrate; stems without hyalodermis; alar cells yellowish, not in auricles.

98

98. Alar cells uniform, without an enlarged basal row; stem apices flattened.

 Callicladium

98. Alar cells with an enlarged basal row; stem apices not flattened.

99

99. Alar cells rounded to the insertion; exostome teeth furrowed.

Acroporium

99. Alar cells not rounded to insertion; exostome teeth not furrowed.

100

100. Exostome teeth striate; endostome with evident basal membrane and segments; eastern North America.

Sematophyllum

100. Exostome teeth smooth or faintly papillose; endostome fugaceous, appearing absent; restricted to central Florida in oak scrub.

Donnellia

101. Plants with numerous (more than 50), quadrate alar cells, extending up the margins by more than 12 rows. 

102

101. Plants with fewer (less than 25), quadrate to rectangular alar cells, extending up the margins in less than 8 rows. 

107

102. Stems with numerous paraphyllia.

Alsia

102. Stems lacking paraphyllia.

103

103. Leaves less than 0.8 mm long; cells with obscure cuticular roughenings; western montane.

Leptopterigynandrum

103. Leaves more than 1 mm long; cells smooth.

104

104. Alar cells extending up the margins for less than 1/6 the leaf length.

105

104. Alar cells extending up the margins for more than 1/3 the leaf length.

106

105. Leaves acuminate, somewhat decurrent; endostome with cilia; plants restricted to coastal western North America, California to British Columbia.

Tripterocladium

105. Leaves mostly obtuse to acute, rarely acuminate, never decurrent; endostome lacking cilia; plants widespread but not in coastal western North America.

Entodon

106. Secondary stems freely subpinnately branched.

Forsstroemia

106. Secondary stems simple or with few branches.

Leucodon

107. Plants epiphytic with creeping primary stems and erect secondary stems.

108

107. Plants terrestrial or rarely on bases of trees, primary and secondary stems not differentiated.

109

108. Secondary stems unbranched; leaves spreading with squarrose tips; propagula common.

Jaegerina

108. Secondary stems irregularly branched; leaves erect; propagula absent.

Neomacounia

109. Stems with hyalodermis; leaf margins serrulate to base.

Herzogiella

109. Stems without hyalodermis; leaf margins entire or serrulate above.

110

110. Leaves plicate.

Orthothecium

110. Leaves not plicate.

111

111. Leaf apices obtuse-apiculate.

112

111. Leaf apices acuminate.

113

112. Plants occurring in fens; stems green, sparsely branched.

Pseudocalliergon

112. Plants widespread in acidic habitats of the boreal forest; stems reddish-orange, pinnately branched.

Pleurozium

113. Leaf cells porose throughout; pseudoparaphyllia absent or foliose; plants in boreal, arctic and alpine habitats.

Orthothecium

113. Leaf cells not porose except at insertion; pseudoparaphyllia filamentous; plants of coastal eastern North America inland to the Midwest.

Isopterygium

114. Plants erect, dendroid or frondose from a nonbranched stipe. 

115

114. Plants prostrate to erect, simple to pinnately branched.

121

115. Leaves bordered by elongate cells.

116

115. Leaves not bordered.

117

116. Plants with two kinds of leaves, the larger ones with costa ending well below apex, the smaller ones (amphigastria) with excurrent costa.

Hypopterygium

116. Plants with leaves all of one kind, the costa subpercurrent.

Leucolepis

117. Stems with paraphyllia or filamentous, paraphyllia-like structures.

 118

117. Stems without paraphyllia.

120

118. Plants epiphytic; stems pinnately frondose, curled when dry, spreading when moist.

Dendroalsia

118. Plants terrestrial (rarely on tree bases); stems dendroid, little altered when dry.

119

119. Branch leaves long-decurrent, the decurrencies of inflated, hyaline cells; stems with lamellae; stem leaves with entire margins.

Pleuroziopsis

119. Branch leaves cordate to auriculate, the auricles not inflated; stems with paraphyllia; stem leaves with serrate margins. 

Climacium

120. Apical cells of branch leaves rhombic; costa of branch leaves strong, not tapering toward apex. 

Thamnobryum

120. Apical cells of branch leaves long-hexagonal; costa of branch leaves slender, tapering toward apex. 

 Porotrichum

121. Plants blackish, tightly attached to rocks in arctic and montane areas; capsules valvate.

122

121. Plants greenish to blackish, on various substrates; capsules cleistocarpous or operculate, never valvate. 

123

122. Plants occurring on calcareous rocks; capsules not hygroscopic, turbinate, obtuse-conic.

Andreaeobryum

122. Plants occurring on acidic rocks; capsules hygroscopic, when moist elliptic, tapering to a point.

Andreaea

123. Leaves strongly squarrose-recurved wet or dry; plants occurring in fens.

Paludella

123. Leaves erect to squarrose; plants occurring in various habitats.

124

124. Stems with paraphyllia.

125

124. Stems lacking paraphyllia.

142

125. Stems complanate-foliate; stem leaves undulate.

Metaneckera

125. Stems symmetrically foliate; leaves not undulate.

126

126. Alar cells inflated in well marked groups.

127

126. Alar cells mostly not differentiated, if so, not inflated.

128

127. Stem leaves deeply plicate; paraphyllia filamentous, abundant.

Palustriella

127. Stem leaves not plicate; paraphyllia foliose, sparse to abundant.

Cratoneuron

128. Paraphyllia with short cells, 1-3:1.

129

128. Paraphyllia with elongate cells, more than 5:1.

140

129. Cells of paraphyllia papillose.

130

129. Cells of paraphyllia smooth.

134

130. Leaf cells unipapillose.

131

130. Leaf cells pluripapillose.

132

131. Plants once-pinnate; leaf cells papillose on both surfaces.

 Abietinella

131. Plants 2-3-pinnate; leaf cells papillose only at back.

Thuidium

132. Plants large, dioicous; leaf cells papillose only at back.

Thuidium

132. Plants small, autoicous; leaf cells papillose on both surfaces.

133

133. Plants once-pinnate; leaves not incurved when dry; leaf cells strongly bulging; setae smooth.

Rauiella

133. Plants 1-2-pinnate; leaves incurved when dry; leaf cells flat; setae smooth or papillose.

Cyrto-hypnum

134. Papillae of leaf cells large, either forked or elongate and curved; leaves broadly ovate.

Thelia

134. Papillae of leaf cells short, simple; leaves lanceolate to ovate-lanceolate.

135

135. Costa pellucid; leaves usually with hair-points.

Claopodium

135. Costa opaque; leaves lacking hair-points.

136

136. Stem and branch leaves differentiated.

Haplocladium

136. Stem and branch leaves uniform.

137

137. Leaf cells isodiametric or nearly so, hexagonal to short-rhombic.

138

137. Leaf cells elongate, oblong-rhombic to oblong-linear.

139

138. Capsules inclined, asymmetric; exostome teeth striate; plants largely western.

Pseudoleskea

138. Capsules erect, symmetric; exostome teeth pale and papillose; plants largely eastern.

Leskea

139. Capsules erect, symmetric; endostome segments narrow, not keeled.

Lescuraea

139. Capsules inclined, asymmetric; endostome segments broader, keeled.

Pseudoleskea

140. Leaf margins entire to serrulate.

Helodium

140. Leaf margins strongly serrate in upper half.

141

141. Upper leaf cells short, 2-5:1; plants of southeastern United States.

Climacium

141. Upper leaf cells linear, more than 8:1; plants widespread.

Hylocomiastrum

142. Plants whitish; leaves composed mostly of costa, multistratose, with small green cells enclosed between 2 layers of hyaline cells on both surfaces.

143

142. Plants greenish to blackish, rarely whitish; leaves usually with conspicuous lamina, if not green cells and hyaline cells of about equal size with only a single layer of hyaline cells on either side of the green cells.

144

143. Green cells in section 4-sided; plants terrestrial.

Leucobryum

143. Green cells in section 3-sided; plants epiphytic.

Octoblepharum

144. Leaf margins strongly incurved to involute, at least when dry.

145

144. Leaf margins plane to recurved.

149

145. Leaf margins incurved wet or dry.

146

145. Leaf margins incurved when dry, plane when moist.

148

146. Leaf cells papillose; costa with two stereid bands.

147

146. Leaf cells smooth; costa with one stereid band.

Indusiella

147. Capsules exserted, operculate.

Weissia

147. Capsules immersed to emergent, cleistocarpous.

Astomum

148. Costa with single stereid band; peristome present.

Plaubelia

148. Costa with two stereid bands; peristome absent.

Hyophila

149. Plants minute, occurring on soil (or rarely rock), ephemeral, often with persistent protonemata; capsules immersed.

150

149. Plants mostly larger, occurring on various substrates, mostly not ephemeral, or if so, capsules exserted.

161

150. Capsules operculate.

151

150. Capsules cleistocarpous.

152

151. Exothecial cells collenchymatous.

Aphanorrhegma

151. Exothecial cells not thickened at corners.

Physcomitrium

152. Spores few per capsule, more than 100 m in diameter.

153

152. Spores numerous per capsule, less than 60 m in diameter.

154

153. Leaves broadly ovate or elliptic, abruptly narrowed to an awn; plants with slender, subterranean rhizomes.

Lorentziella

153. Leaves oblong to lanceolate, acute to subulate; plants not rhizomatous.

Archidium

154. Leaves ovate to broadly ovate, abruptly cuspidate to apiculate.

155

154. Leaves narrowly lanceolate to oblong; costa subpercurrent to subulate.

157

155. Leaf cells pluripapillose with C-shaped papillae; leaf margins revolute.

Phascum

155. Leaf cells smooth or with 1-2 blunt, conical papillae; leaf margins plane to erect

156

156. Plants bulbiform, occurring on soil; leaves very broad and deeply concave with a reflexed tip..

Acaulon

156. Plants not bulbiform, occurring on the underside of quartz pebbles; leaves oblong-lanceolate to oblong-ovate, the tip not reflexed.

Aschisma

157. Capsules pyriform with a conspicuous stomatose neck.

Bruchia

157. Capsules globose to broadly elliptic without a conspicuously differentiated neck.

158

158. Costa long excurrent, at least on perichaetial leaves.

Pleuridium

158. Costa subpercurrent.

159

159. Leaf margins spinose-serrulate throughout.

Ephemerum

159. Leaf margins entire or serrulate above.

160

160. Leaves lanceolate.

Pseudephemerum

160. Leaves oblong-lanceolate to obovate.

Physcomitrella

161. Neck of capsules (apophysis) as wide or wider than upper portion (urn); occurring on dung and animal remains. 

162

161. Neck of capsules considerably narrower than urn; occurring on various substrates.

164

162. Capsules dumb-bell shaped when mature; seta hyaline; restricted to the arctic.

Aplodon

162. Capsules (at least the urn) cylindric; seta colored; widespread.

163

163. Apophyses narrowly pyriform, the same color or darker than the urn; peristome teeth joined in 4's, later in 2's, not chambered. 

Tetraplodon

163. Apophyses globose to turbinate, sometimes becoming umbrella-like, differentiated in color; peristome teeth sometimes approximate or fused in pairs, chambered.

Splachnum

164. Leaves of two kinds, large lateral ones and smaller dorsal ones.

165

164. Leaves all of one kind.

166

165. Leaves bordered; plants erect, occurring along the Pacific coast.

Epipterygium

165. Leaves unbordered; plants prostrate, restricted to southern Florida.

Racopilum

166. Capsules cleistocarpous; plants rare.

167

166. Capsules operculate; plants rare to common.

169

167. Plants known only from New Hampshire; occurring on wet soil.

Bruchia

167. Plants known from arctic and alpine tundra on animal-derived substrates.

168

168. Capsules broadest in lower half.

Voitia

168. Capsules broadest in upper half.

Tetraplodon

169. Cells with nodulose-wavy walls throughout the leaf, sometimes most conspicuous toward leaf base when upper cells short. 

Racomitrium

169. Cells without nodulose-wavy walls, or if present only near insertion.

170

170. Leaves with hyaline hair-points.

171

170. Leaves without hair-points, or if with hairpoints not hyaline.

181

171. Costa broad, filling 1/4 or more of the leaf base.

Campylopus

171. Costa narrower.

172

172. Upper leaf cells densely pluripapillose with C-shaped papillae.

173

172. Upper leaf cells smooth or with low, indistinct papillae.

174

173. End walls of basal cells thickened; calyptrae large, mitrate and covering capsule.

Encalypta

173. End walls of basal cells not thickened; calyptrae small, cucullate.

Tortula

174. Cells smooth, lax, thin-walled, hexagonal to rhombic.

175

174. Cells obscurely papillose, firm-walled, rounded to quadrate.

177

175. Leaves not bordered.

Stegonia

175. Leaves bordered.

176

176. Plants usually epiphytic; capsules erect.

Brachymenium

176. Plants terrestrial or saxicolous; capsules inclined.

Bryum

177. Plants occurring on trees.

Orthotrichum

177. Plants occurring on rocks and soil.

178

178. Perichaetial leaves differentiated in size and shape; capsules immersed.

Schistidium

178. Perichaetial leaves similar to upper vegetative leaves; capsule immersed or exserted.

179

179. Calyptrae scarcely longer than the operculum, cucullate or mitrate, smooth.

Grimmia


179. Calyptrae large, covering the capsule to the middle or below, campanulate-mitrate, striate or plicate. 

180

180. Leaves lanceolate; annuli none; calyptrae plicate.

Coscinodon

180. Leaves ovate to obovate; annuli well developed; calptrae striate.

Jaffueliobryum

181. Costa very broad, occupying 1/3-1/2 the leaf base and filling the subula (plants entirely acrocarpous).

182

181. Costa narrower, or if broad then ending below the leaf apex and not filling it (or if broad then pleurocarpous). 

187

182. Alar cells well diffentiated.

183

182. Alar cells poorly differentiated.

185

183. Costa without guide cells or stereids, in transverse section with a median layer of green cells enclosed dorsally and ventrally with hyaline cells.

Paraleucobryum

183. Costa nearly always with guide cells and stereids, without enclosed green cells.

184

184. Inner basal cells of leaf pale, enlarged, and broadly rectangular, extending upward along the costa; capsules smooth; annuli none; calyptrae not fringed.

Dicranodontium

184. Inner basal cells not conspicuously differentiated along the costa; capsules furrowed; annuli compound; calyptrae usually fringed.

Campylopus

185. Capsules with a neck at least as long as the urn; costa filling no more than 1/3 of the leaf base. 

Trematodon

185. Capsules with a short, inconspicuous neck; costa filling 1/2 or more of the leaf base.

186

186. Leaves 3.5-5.0 mm long; upper laminal cells elongate, 75-140 m long; brood leaves absent.

Campylopodiella

186. Leaves 2.0-3.0 mm long; upper laminal cells rectangular, 25-55 m long; brood leaves usually present, often abundant. 

Brothera

187. Plants pleurocarpous (sporophytes lateral); stems mostly prostrate with lateral branches, often mat- forming, or stems prostrate with erect branches bearing terminal sporophytes (cladocarpous).

188

187. Plants acrocarpous (sporophytes terminal); stems erect, not branched or occasionally branched beneath inflorescences. 

280

188. Leaves bordered by elongate cells, sharply differentiated from shorter inner cells.

189

188. Leaves not bordered by elongate cells.

191

189. Plants epiphytic; border unistratose.

Daltonia

189. Plants aquatic; border 2-5-stratose.

190

190. Margins serrate almost to base; leaves ovate-oblong to ovate-lanceolate, acuminate; plants of Oregon

Limbella

190. Margins serrulate; leaves ovate, often broadly so, bluntly acute; plants of eastern North America.

Platylomella

191. Leaf cells papillose or prorulose.

192

191. Leaf cells smooth.

205

192. Leaves rugose and plicate.

Rhytidium

192. Leaves not rugose, rarely plicate.

193

193. Leaf cells pluripapillose.

194

193. Leaf cells unipapillose or prorulose.

198

194. Papillae arranged in a row over the cell lumina; cells longer than 3:1.

195

194. Papillae randomly arranged over the cells; cells more or less isodiametric.

196

195. Plants stiff, dark green to blackish; leaves ovate, plicate, cordate.

Papillaria

195. Plants soft, bright green (when alive); leaves lanceolate, smooth, not cordate.

Barbella

196. Leaf apices fragile.

Haplohymenium

196. Leaf apices not fragile.

197

197. Leaves strongly inrolled when dry; marginal basal cells elongate, smooth; sporophytes terminal on branches. 

Macromitrium

197. Leaves loosely erect to contorted; marginal basal cells rounded, papillose; sporophytes lateral. 

Anomodon

198. Cells unipapillose over the lumina.

199

198. Cells prorulose.

201

199. Upper leaf cells linear-flexuose; uniseriate propagula common in leaf axils.

Henicodium

199. Upper leaf cells short, 1-3:1; asexual reproduction absent or by branchlets.

200

200. Leaves ovate-lanceolate, narrowed to a nonpapillose, pale acumen, squarrose when moist. 

Lindbergia

200. Leaves oblong-ovate, bluntly acute, loosely erect and more or less complanate.

Stereophyllum

201. Leaf cells short, 1-3:1.

202

201. Leaf cells more than 5:1.

203

202. Leaves appressed when dry, wide-spreading when moist; perichaetial leaves strongly differentiated; capsules immersed.

Cryphaea

202. Leaves little altered when moist; perichaetial leaves scarcely differentiated; capsules exserted.

Lescuraea

203. Plants epiphytic with inconspicuous, creeping, primary stem and erect secondary stems; costa subpercurrent. 

Pireella

203. Plants terrestrial and epiphytic, with primary and secondary stems not differentiated; costa ending well below the apex. 

204

204. Leaves decurrent; setae rough; capsules inclined; plants largely terrestrial.

Bryhnia

204. Leaves not decurrent; setae smooth; capsules erect; plants epiphytic or saxicolous.

Isothecium

205. Leaf apices rounded-obtuse to truncate.

206

205. Leaf apices acuminate to bluntly acute.

212

206. Leaf apices truncate.

Neckeropsis

206. Leaf apices rounded-obtuse.

207

207. Upper leaf cells less than 3:1.

208

207. Upper leaf cells (not apical ones) more than 5:1.

209

208. Plants strongly complanate, shiny, little altered when moist.

Homalia

208. Plants at best weakly complanate, dull, strongly incurved when dry, erect when moist.

Leptodon

209. Alar cells inflated.

210

209. Alar cells not at all inflated.

211

210. Plants strongly julaceous; leaves concave; occurring in or near streams.

Scleropodium

210. Plants with loosely spreading leaves; leaves only slightly concave; occurring in fens.

Calliergon

211. Costa ending in a spine.

Platyhypnidium

211. Costa not projecting at apex.

Hygrohypnum

212. Upper leaf cells 1-2:1.

213

212. Upper leaf cells more than 5:1.

227

213. Sporophytes terminal on erect branches; upper cells rounded.

214

213. Sporophytes lateral; upper cells rhombic to subquadrate.

217

214. Basal marginal cells short, rounded-quadrate.

215

214. Basal marginal cells elongate.

216

215. Upper leaf cells strongly bulging; leaves lanceolate; calyptrae hairy, mitrate.

Macrocoma

215. Upper leaf cells flat; leaves oblong-lanceolate; calyptrae naked, cucullate.

Drummondia

216. Inner basal leaf cells subquadrate to rounded; calyptrae short, plicate.

Groutiella

216. Inner basal cells linear; calyptrae long, not plicate.

Schlotheimia

217. Costa strongly flexuose above; leaf margins with multicellular teeth.

Herpetineuron

217. Costa straight or faintly flexuose; leaf margins entire to serrulate.

218

218. Costa ending in the leaf apex.

219

218. Costa ending well below the leaf apex.

223

219. Upper leaf cells thick-walled, rounded-quadrate to elliptic.

220

219. Upper leaf cells firm-walled, short-oblong to rhombic.

222

220. Plants with clusters of axillary brood branchlets.

Leskeella

220. Plants without brood branchlets.

221

221. Alar cells extending to the costa; inner basal cells not differentiated; peristome white. 

Lindbergia

221. Alar cells restricted in 5-6 rows along the margins, not reaching the costa; inner basal cells long rectangular; peristome yellow. 

Pseudoleskeella

222. Costa relatively narrow, less than 35 m wide at base; plants terretrial.

Amblystegium

222. Costa relatively broad, mostly more than 50 m at base; plants aquatic.

Hygroamblystegium

223. Plants with secondary stems erect and branched.

224

223. Plants without differentiated secondary stems, prostrate.

225

224. Leaf apices shortly acuminate; leaves more than 1 mm long; plants eastern.

Forsstroemia

224. Leaf apices broadly acute; leaves less than 1 mm long; plants western.

Porotrichum (Bryolawtonia)

225. Leaves acuminate, often homomallous.

Pseudoleskeella

225. Leaves bluntly acute.

226

226. Leaves obliquely asymmetric at tip; exostome teeth cross-striate; plants boreal and arctic.

Myrinia

226. Leaves symmetric; exostome teeth rudimentary; plants of southeastern North America.

Clasmatodon

227. Plants bearing long, deciduous, flagelliform branches.

Pseudocryphaea

227. Plants without flagelliform branches.

228

228. Plants with inconspicuous, creeping primary stems with reduced leaves and erect, leafy secondary stems.

229

228. Plants without differentiated stems.

232

229. Secondary stems mostly unbranched.

Jaegerina

229. Secondary stems irregulary pinnate.

230

230. Costa toothed at back on secondary stem leaves; branch leaves acute.

Bestia

230. Costa smooth at back; branch leaves acuminate.

 231

231. Leaf margins revolute nearly throughout, serrate above, often with reflexed teeth; costa often with supplementary costae; western in distribution (disjunct in Newfoundland).

Antitrichia

231. Leaf margins reflexed, entire to serrulate; costa without supplementary costae; eastern in distribution.

Forsstroemia

232. Plants aquatic, coarse; costa broad, more than 100 m wide at base, bluntly excurrent.

233

232. Plants of various habitats; costa much narrower, ending below the apex to excurrent, if excurrent then finely so.

234

233. Costa about 1/3 the width of the leaf base; the lamina with multistratose streaks.

Donrichardsia

233. Costa about 1/4 the width of the leaf base; the lamina unistratose throughout.

Hygroamblystegium

234. One side of stems for entire length covered by reddish rhizoidal tomentum; leaves strongly plicate.

Tomentypnum

234. Tomentum, if present, restricted to extreme base of stems; leaves plicate or not.

235

235. Leaves falcate-secund.

236

235. Leaves straight.

248

236. Stems with a hyalodermis.

237

236. Stems without a hyalodermis.

239

237. Leaves strongly plicate, distinctly denticulate in upper portion.

Sanionia

237. Leaves striolate to plane, entire to slightly denticulate.

238

238. Alar cells inflated; plants occurring in streams.

Hygrohypnum

238. Alar cells poorly differentiated; plants occurring in rich fens.

Limprichtia

239. Plants of upland habitats; leaves plicate.

Brachythecium

239. Plants of wet habitats; leaves not plicate.

240

240. Leaves keeled, distinctly to obscurely 3-ranked; endostome segments joined at tips.

Dichelyma

240. Leaves not keeled or 3-ranked; endostome segments free.

241

241. Costa excurrent.

242

241. Costa subpercurrent.

244

242. Alar cells poorly differentiated.


Drepanocladus

242. Alar cells abruptly inflated.

 243

243. Leaf margins entire.

Drepanocladus

243. Leaf margins finely denticulate.

Warnstorfia

244. Leaf margins finely denticulate at apex.

Warnstorfia

244. Leaf margins entire throughout.

245

245. Plants on rocks in mountain streams.

Hygrohypnum

245. Plants in fens and seeps, not on rocks.

246

246. Cells in lower half of leaf porose; plants of the arctic.

Loeskypnum

246. Cells not porose except at extreme insertion; plants widespread.

247

247. Stems with central strand.

Drepanocladus

247. Stems without central strand.

Hamatocaulis

248. Leaves 3-ranked, conduplicate.

Brachelyma

248. Leaves not 3-ranked or conduplicate.

249

249. Plants pendulous from branches; stem leaves with capillary points; branch leaves recurved; plants restricted to southernmost Florida.

Zelometeorium

249. Plants terrestrial to epiphytic, never pendulous; stem leaves with shorter points; branch leaves mostly not squarrose; plants mostly more northern.

250

250. Leaf cells long hexagonal, less than 8:1.

251

250. Leaf cells linear, more than 10:1.

258

251. Leaves broadly ovate, deeply concave; restricted to Alaska.

Myuroclada

251. Leaves lanceolate to ovate, not or only slightly concave; widespread.

252

252. Plants epiphytic.

253

252. Plants terrestrial and saxicolous.

 254

253. Leaf margins entire; leaf apex gradually acuminate; peristome double and reflexed.

Anacamptodon

253. Leaf margins mostly toothed; leaf apex piliferous; peristome single to absent.

Fabronia

254. Leaf apices piliferous.

Fabronia

254. Leaf apices acute to acuminate.

255

255. Upper leaf cells thick-walled, with rounded ends; capsules erect.

Pseudoleskeella

255. Upper leaf cells firm-walled, with pointed ends; capsules inclined.

256

256. Plants on soil in dry habitats, especially prairies.

Brachythecium

256. Plants on logs and soil in mesic to wet habitats.

257

257. Leaves greater than 1 mm long.

Leptodictyum

257. Leaves less than 1 mm long.

Amblystegium

258. Plants attached to rocks in fast-flowing streams and beside waterfalls.

Platyhypnidium

258. Plants in various habitats but not on rocks in fast-flowing water.

259

259. Plants terrestrial, large, coarse, erect; stems pinnately branched.

260

259. Plants various, prostrate to ascending, if erect then in wetlands; branching various.

261

260. Stem leaves ovate-lanceolate, acuminate to filiform, plicate; plants on litter in coniferous forests.

Trachybryum

260. Stem leaves ovate-oblong, abruptly apiculate, not plicate; plants in lawns and gardens. 

Pseudoscleropodium

261. Leaves plicate.

262

261. Leaves not plicate.

264

262. Branches curved-ascending when dry.

Homalothecium

262. Branches prostrate.

263

263. Leaf apices coarsely serrate; upper leaf cells thick-walled; alar cells well differentiated, quadrate; plants rigid. 

Palamocladium

263. Leaf apices entire to serrulate; upper leaf cells firm-walled; alar cells mostly differentiated, short-rectangular; plants soft.

Brachythecium

264. Plants on tree trunks; calyptrae sparsely hairy; setae rough; plants of eastern U.S..

Homalotheciella

264. Plants not on tree trunks except rarely at bases, if on trees plants of western North America; calyptrae naked; setae usually smooth, rarely rough.

265

265. Plants terete, at least at apex; leaves broadly oblong to ovate, concave to cucullate.

266

265. Plants with spreading leaves; leaves lanceolate, not or scarcely concave.

272

266. Leaves abruptly acuminate.

267

266. Leaves broadly acute to obtuse, sometimes with a minute apiculus.

269

267. Costa with one or more spines at the tip; plants of western North America.

Scleropodium

267. Costa without spines at tip; plants widespread.

268

268. Leaf apex filiform, flat.

Cirriphyllum

268. Leaf apex broader, twisted.

Bryoandersonia

269. Leaves with minute apiculus.

270

269. Leaves not apiculate.

271

270. Plants green; basal leaf cells porose.

Loeskypnum

270. Plants reddish; basal leaf cells not porose.

Sarmenthypnum

271. Leaves obtuse; plants occurring in fens and swamps; widespread.

Calliergon

271. Leaves broadly acute; plants occurring on moist rocks and soil; Pacific coast.

Scleropodium

272. Branch leaves with apical cells about 1/2 the length of those at midleaf.

Eurhynchium

272. Branch leaves with apical cells scarcely shorter than those at midleaf.

273

273. Leaf apices twisted; stems often complanate-foliate.

Steerecleus

273. Leaf apices flat; stems rarely complanate-foliate.

274

274. Leaves with channeled leaf apices from a concave base, with a narrow insertion.

Campylium

274. Leaves without channeled leaf apices, the leaf base not concave or with a narrow insertion.

275

275. Alar cells numerous and quadrate with more on one side of the costa than the other, collenchymatous; plants of southernmost Florida.

Entodontopsis

275. Alar cells few, symmetrically arranged, not collenchymatous; plants widespread.

276

276. Branch and stem leaves strongly differentiated; opercula long rostrate.

Eurhynchium

276. Branch and stem leaves scarcely differentiated; opercula conic to apiculate.

277

277. Costa percurrent or nearly so.

278

277. Costa ending well below leaf apex.

279

278. Costa indistinct at midleaf, not toothed; setae smooth; propagula uniseriate, often formed on back of costa at apex.

Conardia

278. Costa distinct throughout, toothed at back above; setae rough; propagula not present.

Brachythecium

279. Leaves wide-spreading with entire margins; stems complanate-foliate, plants occurring in wet habitats. 

Leptodictyum

279. Leaves erect to spreading with serrulate margins, rarely entire; stems not complanate-foliate, plants occurring in various habitats.

Brachythecium

280. Capsules large, sessile, asymmetric.

Diphyscium

280. Capsules smaller, usually exserted, symmetric.

281

281. Costa ridged at back.

282

281. Costa smooth or toothed at back, not ridged.

283

282. Leaf cells rounded-oblate.

Dryptodon

282. Leaf cells long-rectangular, more than 5:1.

Dicranum

283. Conspicuous clusters of dark rhizoids obscuring the stem.

284

283. Rhizoids inconspicuous or if obvious, never obscuring the stem.

287

284. Leaf cells strongly unipapillose on both surfaces.

Aulacomnium

284. Leaf cells smooth or prorulose.

285

285. Leaves narrowly lanceolate from an ovate base.

Anacolia

285. Leaves ovate to broadly elliptic.

286

286. Rhizoidal (macronematal) initials in longitudinal rows; endostome fused into a dome.

Cinclidium

286. Rhizoidal initials not in longitudinal rows; endostome segments free.

Rhizomnium

287. Plants blackish, occurring on wet rocks usually near streams or the sea, never with propagula.

288

287. Plants greenish, occurring in various habitats, rarely on wet rocks by streams, with or without propagula. 

290

288. Leaf bases with submarginal band of elongate cells.

Scouleria

288. Leaf bases without differentiated submarginal cells.

289

289. Leaf margins incurved.

Grimmia

289. Leaf margins plane to recurved.

Schistidium

290. Hyaline basal cells extending up the margins farther than at the costa, forming a V-shaped area. 

291

290. Hyaline basal cells if present extending more or less equally up the margins as costa or farther up the costa. 

293

291. Upper cells bulging but not papillose.

Luisierella

291. Upper cells pluripapillose.

292

292. Leaves squarrose-recurved from an erect base when moist; leaf margins serrulate above; sporophytes lateral. 

Pleurochaete

292. Leaves erect-spreading to spreading from an erect base when moist; leaf margins entire to notched; sporophytes terminal.

Tortella

293. Plants glaucous, bluish-green.

Saelania

293. Plants not glaucous or bluish.

294

294. Leaves bordered by 2 or more rows of elongate cells.

295

294. Leaves unbordered or if bordered then by only a single row of somewhat elongate cells, or by short cells.

309

295. Leaf margins entire.

296

295. Leaf margins toothed, sometimes obscurely so.

300

296. Leaf cells longer than 3:1.

297

296. Leaf cells 1-2:1.

298

297. Leaf cells in oblique rows; leaves rounded-obtuse, bluntly apiculate.

Pseudobryum

297. Leaf cells not in obvious rows; leaves various.

Bryum

298. Rhizoidal (macronematal) initials in longitudinal rows; endostome fused to a dome.

Cinclidium

298. Rhizoidal initials not in longitudinal rows; endostome segments free.

299

299. Leaves bluntly acute; border unistratose; stems blackish; stomates superficial.

Cyrtomnium

299. Leaves emarginate, rounded-apiculate; border various; stems reddish; stomates immersed.

Rhizomnium

300. Leaves lanceolate from an expanded base, the base with numerous, abruptly hyaline cells.

Syrrhopodon

300. Leaves without expanded base, without hyaline cells.

301

301. Leaf margins with paired teeth.

302

301. Leaf margins with single teeth.

304

302. Leaf cells strongly bulging.

Trachycystis

302. Leaf cells flat.

303

303. Some leaves with low, inconspicuous lamellae; costa in transverse section with two stereid bands; peristome of 32 small teeth attached at tips to a tympanum.

Atrichum

303. No leaves with lamellae; costa with or without a single stereid band; exostome of 16 free teeth. 

Mnium

304. Leaves rugose wet or dry; plants restricted to Pacific Northwest.

Roellia

304. Leaves flat when wet, contorted but not rugose when dry; plants widespread.

305

305. Leaf cells shorter than 2:1.

Plagiomnium

305. Leaf cells 3:1 or more.

306

306. Stems rosulate-foliate, occurring erect from a horizontal underground stem; sporophytes often clustered. 

Rhodobryum

306. Stems foliate throughout, without rhizome-like connections between erect stems; sporophytes not clustered. 

307

307. Leaf cells in oblique rows; leaves rounded-obtuse, apiculate.

Pseudobryum

307. Leaf cells not in obvious rows; leaves broadly acute to acuminate.

308

308. Capsules erect and symmetric; endostome with a high basal membrane, segments lacking or rudimentary, cilia absent.

Brachymenium

308. Capsules inclined and asymmetric; endostome with a keeled basal membrane, keeled and perforate segments, and usually with cilia.

Bryum

309. Leaf margins with paired teeth.

310

309. Leaf margins with single teeth or entire.

315

310. Leaf bases with abruptly differentiated colorless cells (cancellinae); propagula borne on costa near apex. 

Syrrhopodon

310. Leaf bases without cancellinae; propagula absent.

311

311. Leaf cells smooth.

312

311. Leaf cells prorulose or with fine cuticular ridges.

313

312. Leaves elliptic to ovate-elliptic.

Mnium

312. Leaves linear-lanceolate.

Pyrrhobryum

313. Upper leaf cells with cuticular ridges; stems triangular in transverse section.

Plagiopus

313. Upper leaf cells prorulose; stems round in transverse section.

314

314. Leaves crispate when dry.

Bartramia

314. Leaves straight when dry.

Philonotis

315. Leaf cells strongly bulging on one or both surfaces, not papillose.

316

315. Leaf cells flat, smooth or papillose, or if bulging then papillose.

318

316. Leaf laminae bistratose.

Timmiella

316. Leaf laminae unistratose.

317

317. Plants with sheathing leaf bases.

Timmia

317. Plants without sheathing leaf bases.

Bryobrittonia

318. Leaves with abruptly expanded, sheathing leaf bases.

319

318. Leaves with leaf bases not or only gradually expanded, rarely sheathing.

326

319. Leaf cells papillose (at least on sheath) or prorulose.

320

319. Leaf cells smooth.

321

320. Leaf cells papillose over the lumina.

Timmia

320. Leaf cells prorulose.

Bartramia

321. Upper leaf cells quadrate.

322

321. Upper leaf cells short-rectangular.

323

322. Capsules inclined and asymmetric, strumose; plants widespread.

Oncophorus

322. Capsules erect, symmetric, not strumose; plants restricted to southwestern U.S..

Symblepharis

323. Awns roughened throughout by projecting cell ends.

Trichodon

323. Awns smooth or only rough at apex.

324

324. Capsules with neck as long as or longer than the urn.

Trematodon

324. Capsules with neck much shorter than the urn.

325

325. Capsules erect, cylindric, smooth; peristome teeth irregularly perforate or deeply cleft into terete, sometimes filiform divisions.

Ditrichum

325. Capsules inclined, oblong, smooth or furrowed, if erect then furrowed; peristome teeth flat, split 1/2 way down, vertically pitted.

Dicranella

326. Alar cells enlarged, colored, or inflated.

327

326. Alar cells scarcely differentiated.

333

327. Upper and median leaf cells with coarse, irregular cuticular ridges, resembling papillae in transverse section; capsules cylindric, smooth, erect.

328

327. Leaf cells without cuticular ridges; capsules various.

329

328. Leaves with clusters of spherical propagula at leaf apex; leaf margins bistratose.

Grimmia

328. Leaves without propagula; leaf margins unistratose.

Dicranoweisia

329. Costa with 2 stereid bands.

Dicranum

329. Costa without stereids.

330

330. Capsules curved, strumose; plants on alpine rocks.

Kiaeria

330. Capsules erect, not strumose; plants widespread.

331

331. Capsules cylindric; plants usually terrestrial or on tree trunks, rarely on rock.

Dicranum

331. Capsules short, obovoid to pyriform; plants on rocks.

332

332. Capsules ribbed when dry; peristome vertically pitted-striolate below.

Arctoa

332. Capsules smooth when dry; peristome papillose.

Blindia

333. Leaf cells smooth.

334

333. Leaf cells papillose or prorulose.

398

334. Asexual propagula borne on the leaf surfaces.

Rhachithecium

334. Asexual propagula absent, axillary or on leaf apices or specialized structures.

335

335. Leaves ovate to obovate, broadly obtuse, with the costa ending below the leaf apex

336

335. Leaves linear, ovate-lanceolate, ligulate to ovate, acuminate to acute or awned, with costa ending below the apex to excurrent..

342

336. Leaf apices cucullate.

Globulinella

336. Leaf apices not cucullate.

337

337. Plants with large, multicellular propagula in leaf axils; leaves obovate, with cilia on the basal margins. 

Oedipodium

 

337. Plants without axillary propagula; leaves ovate to spatulate, eciliate.

338

 

338. Plants small and bulbiform, on dry soil; leaves concave and imbricate.

Stegonia

 

338. Plants small to medium-sized, never bulbiform, on moist soil; leaves flat to concave, mostly not imbricate.

339

 

339. Leaf cells short-rectangular, lax, thin-walled; capsules erect.

340

 

339. Leaf cells long-hexagonal, firm-walled; capsules inclined to horizontal.

341

 

340. Apical marginal leaf cells short-rhombic, oblong- hexagonal internally; capsules without a distinct neck; plants of southern United States.

Splachnobryum

 

340. Apical marginal leaf cells laxly rectangular, similar to internal ones; capsules with well differentiated neck; plants northern.

Tayloria

 

341. Plants whitish-green, terete; upper leaf cells long, 7-9:1.

Anomobryum

 

341. Plants reddish or green, not terete; upper cells shorter, 2-6:1.

Bryum

 

342. Leaves oblong, lingulate to ovate.

343

 

342. Leaves lanceolate to linear.

368

 

343. Leaf cells rounded to quadrate, more or less isodiametric.

344

 

343. Leaf cells short-rectangular to linear.

353

 

344. Leaf bases with abruptly differentiated, hyaline cells (cancellinae); leaf apices often with propagula. 

Calymperes

 

344. Leaf bases without cancellinae although sometimes gradually hyaline; leaf apices without propagula. 

 345

 

345. Costa excurrent to ending in the cusp; leaf apex cuspidate to piliferous.

346

 

345. Costa subpercurrent; leaf apex broadly acute or obtuse to rarely mucronate.

349

 

346. Leaf apices piliferous.

Desmatodon

 

346. Leaf apices cuspidate.

347

 

347. Plants with rhizoidal tubers, known only from Louisiana; capsules unknown.

Tortula (Chenia)

 

347. Plants lacking tubers, widespread in the north; capsules exserted.

348

 

348. Capsules 0.4-0.8 mm long, obovoid; spores more than 20 m in diameter; peristome absent or rudimentary; plants boreal-temperate.

Pottia

 

348. Capsules 2.5-3.5 mm long, cylindric; spores less than 20 m in diameter; peristome well developed with twisted teeth from a basal membrane; plants of tundra.

Crumia

 

349. Peristome teeth four; propagula cups borne on apices of sterile shoots.

Tetraphis

 

349. Peristome teeth 16; propagula cups absent.

350

 

350. Leaves homomallous, broadly oblong to oblong- ovate, subacute to obtuse.

Aulacomnium

 

350. Leaves not homomallous, oblong to lanceolate, mucronate to acuminate.

351

 

351. Leaves broadly to narrowly lanceolate; peristome double.

Meesia

 

351. Leaves broadly oblong to spatulate; peristome single.

352

 

352. Costa in transverse section with 2 stereid bands.

Barbula

 

352. Costa in transverse section with 1 stereid band.

Scopelophila

 

353. Plants filiform, julaceous (if costa not excurrent see also Anomobryum).

Aongstroemia

 

353. Plants coarser, not julaceous.

354

 

354. Capsules horizontal to pendulous.

355

 

354. Capsules erect.

360

 

355. Capsules curved, asymmetric.

356

 

355. Capsules straight, symmetric.

357

 

356. Exostome shorter than and alternate with endostome.

Plagiobryum

 

356. Exostome longer than and opposite to endostome.

Funaria

 

357. Capsules ovate, less than 1 mm long; stomates none; endostome fused to exostome, cilia none. 

Discelium

 

357. Capsules cylindric to ovate, usually greater than 1 mm long; stomates present; endostome free of exostome, cilia mostly present.

358

 

358. Leaf cells in oblique rows.

Plagiobryum

 

358. Leaf cells not in obvious oblique rows.

359

 

359. Leaf cells 4:1 or less.

Bryum

 

359. Leaf cells 5:1 or longer.

Pohlia

 

360. Peristome absent.

361

 

360. Peristome present.

363

 

361. Calyptrae 4-angled, sheathing the entire capsule until after dehiscence.

Pyramidula

 

361. Calyptrae not angled, not sheathing or persistent.

362

 

362. Capsules subcylindric or narrrowly pyriform; annuli none; exothecial cells oblong to oblong-linear; calyptrae inflated- cucullate.

Entosthodon

 

362. Capsules urceolate to broadly pyriform; annuli present; exothecial cells irregularly hexagonal; calyptrae inflated-mitrate.

Physcomitrium

 

363. Peristome of endostome only, without a center line on the outer surface.

Mielichhoferia

 

363. Peristome double or of exostome only, with a center line on the outer surface.

364

 

364. Plants with scarcely differentiated neck.

365

 

364. Plants with well-differentiated neck (apophysis).

366

 

365. Plants of arctic tundra.

Funaria

 

365. Plants of British Columbia (50 N) and south.

Entosthodon

 

366. Urns black, sometimes with yellow apophyses.

Tetraplodon

 

366. Urns and apophyses green to brown.

367

 

367. Setae pale greenish-white, slender; costa filling the acumen; plants of eastern North America. 

Splachnum

 

367. Setae brownish, stout to slender; costa ending below the leaf apex; plants of western and northern North America. 

Tayloria

 

368. Leaves conspicuously 4-ranked.

Conostomum

 

368. Leaves not conspicuously ranked (if 3-ranked see Meesia).

 369

 

369. Leaf cells short, 1(-2):1, rounded to quadrate.

370

 

369. Leaf cells long, (3-)4:1 or longer, rectangular to long-hexagonal.

386

 

370. Perichaetial leaves strongly differentiated, with an awn as long as the lamina; leaves bistratose.

Diphyscium

 

370. Perichaetial leaves slightly or not differentiated, never long awned; leaves uni- to multistratose.

371

 

371. Capsules distinctly 8 or 16 ribbed and furrowed.

372

 

371. Capsules smooth or indistictly furrowed when dry but without distinct ribs.

378

 

372. Calyptrae mitrate.

373

 

372. Calyptrae cucullate.

375

 

373. Calyptrae hairy.

Ulota

 

373. Calyptrae naked.

374

 

374. Annuli none; calyptrae plicate.

Orthotrichum

 

374. Annuli compound; calyptrae not plicate.

Brachydontium

 

375. Setae cyneous; plants rare, forming tight cushions on alpine slopes.

Oreas

 

375. Setae erect (but sometimes twisted); plants various but not as above.

376

 

376. Capsules abruptly bent at the seta-capsule junction and horizontal, often becoming purple-red when mature. 

Ceratodon

 

376. Capsules erect to suberect and becoming brown when mature.

377

 

377. Peristome teeth divided to half their length; capsules cylindric to ovate-cylindric, ca. 2 mm long; plants of Pacific Northwest.

Cynodontium

 

377. Peristome teeth undivided; capsules ovoid, less than 1 mm long; plants of eastern and midwestern U.S. and maritime Canada.

Rhabdoweisia

 

378. Capsules with an erect, elongate, well defined neck; peristome double.

Meesia

 

378. Capsules with a short, inconspicous neck; peristome single.

379

 

379. Capsules inclined.

380

 

379. Capsules erect.

381

 

380. Capsules less than 1 mm long, black, not strumose; leaf margins unistratose; plants of rich fens.

Catoscopium

 

380. Capsules 1.5-2.0 mm long, pale, strumose; leaf margins bistratose; plants on moist soil, rocks and logs. 

Oncophorus

 

381. Capsules immersed to short-exserted.

Grimmia

 

381. Capsules long-exserted.

382

 

382. Calyptrae mitrate.

383

 

382. Calyptrae cucullate, not plicate.

384

 

383. Calyptrae plicate; setae straight.

Ptychomitrium

 

383. Calyptrae not plicate; setae cygneous.

Campylostelium

 

384. Costa with 1 stereid band; leaf margins bistratose.

Trichostomopsis

 

384. Costa with 2 stereid bands; leaf margins unistratose.

385

 

385. Leaves lanceolate from a somewhat expanded base.

Didymodon

 

385. Leaves oblong.

Barbula

 

386. Leaves subulate.

387

 

386. Leaves acute to acuminate.

394

 

387. Capsules curved and asymmetric.

Dicranella

 

387. Capsules straight, symmetric, although sometimes inclined to pendulous.

388

 

388. Setae flexuose-curved to cygneous.

389

 

388. Setae straight, but sometimes spirally- twisted.

391

 

389. Setae more 10 mm long; plants more than 5 mm tall; leaves more than 4 mm long; capsules pyriform. 

Leptobryum

 

389. Setae less than 5 mm long; plants less than 3 mm tall; leaves less than 2 mm long; capsules hemispheric. 

390

 

390. Plants ephemeral, on soil in Florida; setae stout curved at apex, not twisted; capsules eperistomate. 

Eccremidium

 

390. Plants perennial, on rock, not in Florida; setae slender, twisted; capsules peristomate.

 Seligeria

 

391. Peristome double; plants arctic.

Pseudoditrichum

 

 391. Peristome single; plants widespread.

392

 

392. Capsules ovoid; plants on calcareous rocks.

Seligeria

 

392. Capsules oblong to cylindric; plants generally on soil.

393 

 

393. Capsules long cylindric; peristome teeth divided to base, terete, papillose.

Ditrichum

 

393. Capsules short cylindric; peristome teeth divided half their length, flat, vertically pitted- striolate.

Dicranella

 

394. Costa occupying 1/2 or more of leaf base; capsules curved and asymmetric, elongate-pyriform from a neck as long as the urn.

Amblyodon

 

394. Costa occupying less than 1/4 the leaf base; capsules straight and symmetric, without conspicuous neck. 

395

 

395. Plants small, less than 2 mm high, gregarious, occurring on calcareous rocks; capsules ovate. 

Seligeria

 

395. Plants larger, mostly more than 5 mm, in tufts occurring on various substrates; capsules cylindric. 

396

 

396. Leaves flexuose-twisted when dry; capsules erect; plants occurring in the southern Appalachians and California.

Orthodontium

 

396. Leaves erect, little altered when dry; capsules erect or inclined; plants widespread.

397

 

397. Capsules terminal, inclined to pendent; peristome double; leaves usually more than 1 mm long, sometimes with axillary propagula. 

Pohlia

 

397. Capsules appearing lateral, erect; peristome single; leaves less than 1 mm long, never with propagula.

Mielichhoferia

 

398. Leaves bistratose throughout, ligulate to oblong, obtuse; perichaetial leaves long awned.

Diphyscium

 

398. Leaves unistratose, or if bistratose then not ligulate to oblong; perichaetial leaves not so differentiated. 

399

 

399. Leaf cells rectangular, prorulose; capsules globose, rugulose to furrowed when dry.

400

 

399. Leaf cells rounded-quadrate; uni- to pluripapillose; capsules ovate to cylindric, smooth or furrowed. 

403

 

400. Leaves strongly ranked.

Conostomum

 

400. Leaves not conspicuously ranked.

401

 

401. Capsules erect, or if pendent then from curvature of seta, symmetric, rugulose when dry; peristome reduced to a low membrane.

Bartramidula

 

401. Capsules strongly inclined, asymmetric, furrowed; peristome better developed.

402

 

402. Leaves unistratose; plants on soil and rocks in at least periodically wet habitats, often with innovative branches beneath inflorescences.

Philonotis

 

402. Leaves bistratose at least at margins; plants on banks and cliffs in mesic habitats, without innovative branches. 

Bartramia

 

403. Leaf cells appearing papillose from slightly thickened walls between cells (not prorulose).

404

 

403. Leaf cells papillose over the lumina.

405

 

404. Leaves crispate when dry; capsules long exserted, cylindric; plants usually occurring on logs. 

Dicranoweisia

 

404. Leaves erect, straight to curved; capsules immersed to short exserted, ovate-cylindric; plants occurring on rocks. 

Grimmia

 

405. Leaf cells collenchymatous and stellate.

406

 

405. Leaf cells not thickened in the corners or if so merely rounded and not stellate.

407

 

406. Leaf cells unipapillose; leaves not recurved.

Aulacomnium

 

406. Leaf cells pluripapillose; leaves recurved.

Geheebia

 

407. Leaves with abruptly differentiated hyaline cells occupying most of the leaf base (cancellinae) and with an intramarginal border of elongate cells (teniolae), at least in lower part of leaf; usually with propagula on leaf apex.

Calymperes

 

407. Leaves without cancellinae, or if present then never with teniolae; propagula never on leaf apices but sometimes elsewhere on leaves or in axils.

408

 

408. Plants with propagula borne terminally on specialized stalks from stem apices.

Aulacomnium

 

408. Plants with or without various means of asexual reproduction but these never borne on stalks from the stem apices.

409

 

409. Plants occurring on tree trunks or bare rock, with immersed to shortly exserted, often ribbed capsules. 

410

 

409. Plants usually occurring on soil, if on rocks or trees then capsules long exserted and mostly unribbed (or plants sterile). 

412

 

410. Calyptrae cucullate, not plicate, naked; occurring on wet rocks.

Amphidium

 

410. Calyptrae mitrate, plicate, usually hairy; occurring on tree trunks and dry rocks.

411

 

411. Leaves usually crispate to contorted when dry; basal marginal cells with thickened transverse walls; stomates superficial; capsules shortly exserted.

Ulota

 

411. Leaves usually little altered when dry; basal marginal cells not differentiated; stomates immersed or superficial; capsules immersed to shortly exserted.

Orthotrichum

 

412. Costa in transverse-section more or less homogeneous, without differentiated stereids.

413

 

412. Costa in transverse-section with differentiated stereid bands.

417

 

413. Leaf cells with C-shaped papillae; leaves broadly spatulate.

Gymnostomiella

 

413. Leaf cells with simple, conic papillae; leaves various but not broadly spatulate.

414

 

414. Upper leaf cells with 4-7 small, conic papillae.

Zygodon

 

414. Upper leaf cells with 3 or fewer, simple to branched papillae.

415

 

415. Leaves less than 0.6 mm long, ligulate, rounded- obtuse; rare plants of calcareous rocks; annuli of 2-3 rows of well-differentiated cells.

Gyroweisia

 

415. Leaves more than (0.7-)1.5 mm long, lanceolate to ovate, acuminate to obtuse; annuli poorly differentiated. 

416

 

416. Leaves typically crispate to contorted when dry; basal marginal cells with thickened transverse walls; capsules shortly exserted; calyptrae hairy.

Ulota

 

416. Leaves usually little altered when dry; basal marginal cells not differentiated; capsules immersed to shortly exserted; calyptrae naked (species with contorted leaves) to hairy (species with unaltered leaves).

Orthotrichum

 

417. Costa with a single, dorsal stereid band.

418

 

417. Costa with both dorsal and ventral stereid bands.

429

 

418. Calyptrae campanulate-mitrate, covering entire capsule, often lobed at base; basal leaf cells with thickened transverse walls.

Encalypta

 

418. Calyptrae cucullate, covering only operculum and capsule apex, unlobed at base; basal leaf cells usually without thickened transverse walls.

419

 

419. Leaves linear-lanceolate to lanceolate, never with hair points; leaf margins recurved to plane; leaf cells with papillae conic, clavate or branched, rarely C-shaped.

420

 

419. Leaves broadly lanceolate (from revolute leaf margins), lingulate or oblong-ovate, sometimes with hair points; leaf margins recurved to strongly revolute; leaf cells with papillae stellate from a stipitate base to C-shaped.

424

 

420. Leaf cells with 4-7 widely spaced, small, conic papillae; elliptic propagula present in leaf axils; peristome double; plants usually occurring on trees, rarely on rock.

Zygodon

 

420. Leaf cells with 1-3(-4) closely set, simple to branched papillae; propagula absent; peristome single or absent; plants occurring on soil and rocks.

421

 

421. Leaf margins serrulate above; capsules erect to inclined, often furrowed and strumose; peristome vertically pitted-striolate.

Cynodontium

 

421. Leaf margins entire; capsules erect, never furrowed or strumose; peristome, when present, papillose. 

422

 

422. Basal leaf cells lax and hyaline; upper leaf margins bistratose throughout; peristome present.

Trichostomopsis

 

422. Basal leaf cells firm-walled, pale but not hyaline; upper leaf margins unistratose or irregularly bistratose; peristome absent.

423

 

423. Stem monopodially branched; archegonia on short, lateral branches; stem transverse section rounded- triangular. 

Anoectangium

 

423. Stem sympodially branched; archegonia terminal on main stem; stem transverse section round.

Gymnostomum

 

424. Leaves with an intramarginal band of enlarged, smooth, often orange cells.

Crumia

 

424. Leaves without differentiated intramarginal cells but sometimes with smooth marginal cells, these not enlarged.

425

 

425. Leaves narrowly lanceolate; leaf margins erect and bistratose.

Trichostomopsis

 

425. Leaves oblong, lingulate to ovate; leaf margins plane to revolute, unistratose or if bistratose then always revolute. 


426

 

426. Upper leaf margins broadly revolute to spirally revolute, with cells often more strongly chlorophyllose than median cells.

Pseudocrossidium

 

426. Upper leaf margins plane to revolute, with cells undifferentiated or paler than median cells. 

427

 

427. Leaves unbordered; peristome none or rudimentary.

Pottia

 

427. Leaves often bordered by smooth cells; peristome present.

428

 

428. Peristome teeth united in a high or rarely low, tubular basal membrane, spirally twisted above; cells of adaxial (upper) surface of costa similar to or smaller than laminal cells in transverse section.

Tortula

 

428. Peristome teeth free or rarely united in a low basal membrane, erect to slightly twisted above; cells of adaxial surface of costa mostly larger than or otherwise differentiated from laminal cells in transverse section.

Desmatodon

 

429. Leaf margins abruptly serrate at the shoulder.

Eucladium

 

429. Leaf margins entire at shoulders.

430

 

430. Leaf cells with numerous (more than 7), minute, elliptic papillae over the walls as well as the lumina. 

Amphidium

 

430. Leaf cells with fewer than 7, larger, round papillae only over the lumina.

431

 

431. Leaf margins toothed above.

432

 

431. Leaf margins entire or roughened with projecting papillae.

436

 

432. Laminae bistratose; margins unistratose.

Rhexophyllum

 

432. Laminae unistratose; margins uni- or bistratose.

433

 

433. Leaf cells bulging, mamillose to unipapillose.

Dichodontium

 

433. Leaf cells plane, pluripapillose.

434

 

434. Stems with central strand.

Bryoerythrophyllum

 

434. Stems without central strand.

435

 

435. Stems with hyalodermis; adaxial (upper) surface of costa with enlarged, papillose epidermal cells. 

Paraleptodontium

 

435. Stems without hyalodermis; adaxial surface of costa with small, smooth cells.

Leptodontium

 

436. Leaves at extreme apex with large, curved, projecting papillae.

Dichodontium

 

436. Leaves at extreme apex with margins entire or papillose-crenulate.

437

 

437. Stems triquetrous, especially when moist; leaf cells unipapillose, the papillae sometimes branched; plants of California

Triquetrella

 

437. Stems without ranked leaves; leaf cells pluripapillose; plants widespread.

438

 

438. Stems without central strand, in transverse section with largest cells in middle of section. 

Oxystegus

 

438. Stems with central strand, or if poorly developed in transverse section at least with largest cells not in middle of stem.

439

 

439. Leaf margins plane to erect.

440

 

439. Leaf margins recurved to revolute, at least near midleaf or below.

443

 

440. Stems with hyalodermis.

Trichostomum

 

440. Stems without hyalodermis, epidermal cells small.

441

 

441. Leaf apices subtubulose; upper leaf cells with 1-2 large, centered, multiplex papillae.

Tuerckheimia

 

441. Leaf apices flat; upper leaf cells with 3-6 small, scattered, simple, blunt papillae.

442

 

442. Perichaetia and sporophytes lateral; leaves 2.2-3.0 mm long; axillary hairs of 15-20 cells.

Molendoa

 

442. Perichaetia and sporophytes terminal; leaves less than 2.0 mm long; axillary hairs of 8-10 cells. 

Gymnostomum

 

443. Peristome none; leaves recurved only on one side.

Hymenostylium

 

443. Peristome usually present; leaves recurved on both sides.

444

 

444. Axillary hairs with a brown, slender basal cell; laminal cells well defined in surface view; leaves usually lanceolate; cells of abaxial (back) surface of costa quadrate to short-oblong, rarely elongate; basal laminal cells usually little differentiated, green and short-rectangular.

Didymodon

 

444. Axillary hairs with all cells hyaline; laminal cells obscure in surface view; leaves usually ovate to oblong; cells of abaxial surface of costa oblong to elongate; basal laminal cells usually strongly differentiated, hyaline and elongate.

Barbula