Sp. Musc. Frond., 164. 1801
Plants in lax to dense tufts, dull green to glaucous, sometimes yellowish or yellowish brown distally. Stems 0.5–15 cm, erect, 2-fid, lacking subfloral whorl of branches; rounded in cross section, hyalodermis present, indistinct to distinct, epidermis not prorulose; radiculose proximally, rhizoids papillose. Leaves not in distinct rows or rarely in 5 rows, erect-appressed to spreading or circinate, sometimes flexuose when dry, spreading when moist, narrowly lanceolate to linear, 2- or 3-stratose at margins or throughout; base ± sheathing; margins plane or revolute, entire proximally, serrate to serrulate distally, teeth single or paired; apex acuminate or subulate; costa subpercurrent to excurrent, abaxial surface prominent, rough, or sometimes obscure in distal limb; basal laminal cells elongate to rectangular or linear; distal cells subquadrate to oblong-linear, prorulose on both surfaces, walls firm. Specialized asexual reproduction absent. Sexual condition dioicous, autoicous, or synoicous; perigonia gemmiform; perichaetial leaves little differentiated from stem leaves (differentiated in B. ithyphylla). Seta single (often 2 or 3 per perichaetium in B. halleriana), elongate or rarely short, straight or sometimes curved. Capsule inclined or sometimes erect, subglobose, globose, ovoid, or pyriform, furrowed when dry, mouth oblique; annulus not distinct; operculum convex to conic; peristome double, single, or absent; exostome teeth reddish brown, lanceolate, smooth or papillose, apically free; endostome pale yellow, sometimes absent, segments keeled, cilia rudimentary or absent. Spores reniform to subspheric, coarsely to warty papillose.
Nearly worldwide, except Antarctica, especially diverse in montane tropics.
Species ca. 90 (7 in the flora).
Bartramia is generally recognized by its linear-lanceolate leaves and sheathing base with a distal lamina that is 2- or 3-stratose at the margins or throughout. The plants may be soft or rigid; the stem cortical cells have somewhat firm walls. The leaves are not plicate; the basal laminal cells are pale and smooth with walls thin or rarely thick toward the costa. The perichaetial leaves are usually less prorulose with more lax areolation; the exostome teeth are sometimes cleft distally and lack intermediate abaxial thickenings. Bartramia stricta lacks a sheathing leaf base but otherwise is in accord with the generic concept.
|1||Leaves 4-7 mm; bases laxly or scarcely sheathing; stems to 10(-15) cm||> 2|
|1||Leaves usually 1.5-5 mm; bases sheathing (except B. stricta); stems to 5 cm||> 3|
|2||Setae short, equal to or slightly longer than capsule.||Bartramia halleriana|
|2||Setae many times longer than capsule.||Bartramia pomiformis|
|3||Leaf bases not sheathing, shoulders absent.||Bartramia stricta|
|3||Leaf bases sheathing, shoulders well developed||> 4|
|4||Costae obscure in distal limb; distal laminal cells 25-45 µm, prorulae low.||Bartramia ithyphylla|
|4||Costae prominent in distal limb; distal laminal cells 8-25 µm, prorulae high||> 5|
|5||Leaf shoulders delicate, often eroded; apices fragile, usually broken.||Bartramia potosica|
|5||Leaf shoulders firm, not eroded; apices usually intact||> 6|
|6||Basal laminal cell walls thick toward costa, thin toward margins; leaf margins strongly revolute.||Bartramia brevifolia|
|6||Basal laminal cell walls thin throughout; leaf margins plane distally.||Bartramia subulata|