Stems 0.5–4 (–12) cm, usually comose to evenly foliate; sparsely to densely radiculose. Leaves ovate or ovatelanceolate, distal leaves usually somewhat enlarged; base red or pink, red sap not present in cell lumina; limbidium distinct to indistinct, narrow, pale to green or yellow, 1-stratose throughout; subalar cells inflated, pink, on gametoecial and inner comal leaves; proximal laminal cells rectangular, (short-rectangular in P. pseudotriquetrum), same length as medial, sometimes longer; distal cells rhomboidal to hexagonal, not lax, usually 3–4: 1. Capsule pyriform, ovate, or obovate; endostome sometimes adherent to exostome, segments with narrowly to broadly ovate perforations. Spores 10–50 µm, finely to strongly papillose, yellow, green, brown, or black.

Distribution

North America, South America, Eurasia, Africa, Pacific Islands, arctic, montane, and boreal regions

Discussion

Species ca. 35 (16 in the flora).

Species in subg. Claodium are distinctive in a number of characters, including 1-stratose border, relatively short proximal laminal cells, and tufted or comose habits of many species. Most also have a small group of somewhat inflated pink cells at the leaf insertion in the gametoecial and larger comose leaves, a feature absent from subg. Ptychostomum. The cells at the leaf base usually have red to red-brown walls but clear sap. The leaves are erect-spreading when moist; the setae are red or red-brown (brown in P. salinum).

Selected References

None.

Lower Taxa

Ptychostomum archangelicum, Ptychostomum bimum, Ptychostomum creberrimum, Ptychostomum inclinatum, Ptychostomum intermedium, Ptychostomum knowltonii, Ptychostomum lonchocaulon, Ptychostomum longisetum, Ptychostomum neodamense, Ptychostomum nitidulum, Ptychostomum pallescens, Ptychostomum pendulum, Ptychostomum pseudotriquetrum, Ptychostomum reedii, Ptychostomum salinum, Ptychostomum subneodamense

Key

1	Sexual condition dioicous, autoicous, synoicous, or polyoicous; peristome well developed; endostome basal membrane 1/2 exostome height; spores 10-26(-30) µm	> 2
1	Sexual condition usually synoicous, rarely autoicous or polyoicous; peristome well developed or reduced; endostome basal membrane usually less than 1/2 exostome height; spores (8-)22-30(-50) µm	> 9
2	Sexual condition autoicous; spores 18-22 µm; stems comose, innovations comose or somewhat elongate and evenly foliate.	Ptychostomum pallescens
2	Sexual condition dioicous, synoicous, or polyoicous; spores 10-26(-30) µm; stems tufted or comose, rarely evenly foliate, innovations comose or somewhat elongate and evenly foliate	> 3
3	Sexual condition dioicous; leaf bases strongly decurrent; stems tufted, weakly comose to evenly foliate, usually strongly radiculose well toward stem apices, innovations elongate and evenly foliate; specialized asexual reproduction occasional, by leaf axil gemmae.	Ptychostomum pseudotriquetrum
3	Sexual condition dioicous, synoicous, or polyoicous; leaf bases not or weakly decurrent; stems tufted and/or comose, strongly or weakly radiculose, innovations comose or somewhat elongate and evenly foliate; specialized asexual reproduction absent	> 4
4	Leaves strongly twisted to contorted when dry, concave; apices broadly acute to obtuse; costae usually not reaching apex to percurrent; sexual condition dioicous	> 5
4	Leaves somewhat twisted or contorted when dry, flat to weakly concave; apices acute to acuminate; costae short- to long-excurrent; sexual condition synoicous or polyoicous	> 6
5	Leaves crowded; bases wide.	Ptychostomum neodamense
5	Leaves distant; bases narrow.	Ptychostomum subneodamense
6	Innovations elongate, evenly foliate; leaves not much enlarged toward stem apex; bases weakly decurrent; costae short-excurrent; distal laminal cell walls sometimes very incrassate, sometimes oblique to costa; sexual condition synoicous.	Ptychostomum bimum
6	Innovations comose or somewhat elongate and evenly foliate; leaves usually enlarged toward apex; bases not or weakly decurrent; costae long-excurrent; distal laminal cell walls thin to firm, never oblique to costa; sexual condition synoicous or polyoicous	> 7
7	Sexual condition synoicous; spores (18-)20-26(-30) µm.	Ptychostomum intermedium
7	Sexual condition synoicous or polyoicous; spores 10-18(-20) µm	> 8
8	Sexual condition synoicous; limbidium in 2 or 3 rows, yellowish.	Ptychostomum creberrimum
8	Sexual condition polyoicous; limbidium in (2-)3-4(-6) rows, concolorous.	Ptychostomum lonchocaulon
9	Endostome strongly adherent to exostome; exostome teeth appearing chambered; leaf apices acuminate; costae long-excurrent; capsules pyriform; spores (22-)25-30 (-36) µm.	Ptychostomum pendulum
9	Endostome usually not adherent to exostome; exostome teeth not appearing chambered; leaf apices obtuse, acute, or acuminate; costae not reaching apex to long-excurrent; capsules pyriform or obovate; spores (15-)22-50 µm	> 10
10	Leaves strongly concave, ± imbricate to weakly contorted or shrunken when dry; costae not reaching apex to percurrent, rarely short-excurrent; spores 15-22(-25)µm; capsules short-pyriform, asymmetric, curved; endostome cilia usually present.	Ptychostomum nitidulum
10	Leaves flat or concave, twisted to contorted or shrunken when dry; costae percurrent to long-excurrent; spores (18-)22-50 µm; capsules obovate or short- to elongate-pyriform, symmetric (asymmetric, somewhat curved in P. intermedium); endostome cilia present or absent	> 11
11	Sexual condition autoicous; leaves concave; limbidium indistinct; costae percurrent in proximal leaves to sometimes short-excurrent in distal leaves; specialized asexual reproduction by leaf axil gemmae; spores (28-)30-40 µm.	Ptychostomum reedii
11	Sexual condition synoicous; leaves flat to concave; limbidium strong; costae usually short- to long-excurrent; specialized asexual reproduction absent; spores (18-)20-50 µm	> 12
12	Capsule mouths orange or yellow; endostome basal membrane 1/2 exostome height, cilia present, sometimes reduced; spores (18-)20-26(-30) µm	> 13
12	Capsule mouths yellow or red; endostome basal membrane usually less than 1/2 exostome height, cilia rudimentary or absent; spores (18-)20-50 µm	> 14
13	Cilia rudimentary or sometimes 1 or 2, long, appendiculate to nodose; capsules symmetric, mouths straight.	Ptychostomum inclinatum
13	Cilia long, nodose; capsules asymmetric, mouths oblique.	Ptychostomum intermedium
14	Leaf apices acute to obtuse; costae percurrent to short-excurrent, awns recurved; setae (2-)3-6(-8) cm; spores (18-)20-50 µm	> 15
14	Leaf apices acuminate; costae short- to long-excurrent, awns straight; setae 1-3 cm; spores (18-)22-30 µm	> 16
15	Leaves strongly concave; apices acute to obtuse; costae percurrent to short-excurrent; spores (18-)20-30 µm; setae (2-)3-4 cm.	Ptychostomum knowltonii
15	Leaves weakly concave; apices acute; costae short-excurrent; spores (38-)40-50 µm; setae 3-6(-8) cm.	Ptychostomum longisetum
16	Spores dark brown to black; exostome teeth with pores absent along mid line; endostome sometimes weakly adherent to exostome at base; operculum short-convex, not or weakly apiculate.	Ptychostomum archangelicum
16	Spores pale yellow-brown; exostome teeth with small pores present along mid line at base; endostome not adherent to exostome; operculum long-conic, distinctly apiculate.	Ptychostomum salinum

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