1. Plants rigid, stout; leaves crowded on stem apex, long-elliptical, ligulate, spathulate, broadly round, more than 2.5 mm long..........................................................................................................................2
1. Plants soft, slender; leaves loose on stem apex, ovate-lanceolate, rounded-triangular, oblong-lanceolate, less than 2.5 mm long.................................................................................................................... 6
2. Upper leaf margins bordered by 1–3 rows of differentiated cells..............................................3
2. Upper leaf margins bordered by 3–6 rows of differentiated cells...............................................5
3. Capsules less than 4.0 mm long..........................................................................2. B. capitulatum
3. Capsules more than 4.5 mm long..................................................................................4
4. Leaves broadly spathulate; margins dorsally revolute throughout; apophyses thinner than urn; spores 35–48 μm in diameter..............................................................................................7. B. longicolle
4. Leaves long-spathulate; margins dorsally revolute ca. 2/3 the leaf length; apophyses thicker than urn; spores 25–35 μm in diameter................................................................................................... 10. B. nepalense
5. Plants twisted when dry; upper leaf margins strongly and spinulosely serrate..................8. B. longidens
5. Plants not or only slightly twisted when dry; upper leaf margins minutely serrulate...... 12. B. ptychothecium
6. Leaves densely and imbricately appressed on stems when dry.................................................7
6. Leaves loose, not imbricate on stems when dry......................................................................8
7. Plants slender; long-aristate costal tips straight; median leaf cells long-rhomboidal, vermicular; alar cells clearly differentiated...........................................................................1. B. acuminatum
7. Plants stout; long-aristate costal tips often curved or bent, sometimes divaricate; median leaf cells rhombic or hexagonal; alar cells not clearly differentiated....................................14. B. systylium
8. Plants densely tufted, caespitose, with dense rhizoids; leaves triangularly lanceolate........ 11. B. pendulum
8. Plants loosely tufted, not caespitose, with sparse rhizoids; leaves not triangularly lanceolate.................... 9
9. Plants forming rosettes; leaf apices obtuse; costae ending just below the leaf apex........ 4. B. immarginatum
9. Plants not forming rosettes; leaf apices acute; costae percurrent to excurrent or ending just below the apex............................................................................................................................10
10. Leaves elliptical-lanceolate; costae extending into long awns; capsules pyriform, large; endostome with well-developed cilia............................................................................................................ 6. B. leptophyllum
10. Leaves ovate-lanceolate or narrowly ovate-lanceolate; costae ending in short awns or slightly below the apex; capsules shortly pyriform, small; endostome without cilia.............................................................. 11
11. Costae extending into shortly aristate awns; margins plain at apex.........................................12
11. Costae percurrent or ending below the apex; margins keeled at apex......................................13
12. Leaves oblong-ovate; costae stout; leaf cells thick-walled; alar cells shortly rectangular or nearly quadrate
.................................3. B. exile
12. Leaves cordiform; costae slender; leaf cells thin-walled; alar cells long-rectangular.......... 13. B. sinense
13. Leaves shortly lanceolate, plane at apex; setae 3–4 mm long; spores 17–25 μm in diameter.. 5. B. jilinense
13. Leaves long-lanceolate, keeled at apex; setae ca. 12 mm long; spores 12–18 μm in diameter 9. B. muricola