1. Infertile branches usually with various types of gemmae in leaf axils........................................2
1. Infertile branches usually without gemmae in leaf axils or only with gemmae on rhizoids...................9
2. Gemmae filiform.................................................................................................................3
2. Gemmae globose, ovoid, obovoid, elongate-ovoid to slenderly clavate or slenderly obovoid..................... 4
3. Leaves oblong-ovate, acute at apex; margins nearly entire except at apex; gemmae without distinct leaf primordia........................................................................................... 14. P. leucostoma
3. Leaves narrowly oblong-lanceolate; margins denticulate above the mid-leaf; gemmae with 1–2 leaf primordia..............................................................................................21. P. proligera
4. Gemmae globose, oblong-ovoid or obovoid.......................................................................5
4. Gemmae usually elongate-obovoid, slenderly clavate or elongate-cylindrical.............................................. 7
5. Gemmae few, globose, often with foliate leaf primordia; costae often nearly percurrent... 6. P. drummondii
5. Gemmae numerous, obovoid or elongate-obovoid to nearly cuneiform, usually with 2–3 short leaf primordia; costae ending clearly below the apex................................................................................................... 6
6. Gemmae elongate-obovoid to cuneiform; rhizoids abundant on lower stems; leaves ovate-lanceolate; margins not decurrent at base, clearly serrate above the mid-leaf ................................ 3. P. camptotrachela
6. Gemmae obovoid; rhizoids few; leaves narrowly ovate-lanceolate; margins decurrent at base, entire to serrulate near the apex.....................................................................................16. P. ludwigii
7. Leaf apices narrowly acute; costae thick, ending clearly below the apex; gemmae sometimes ovoid to obovoid, more often elongate-obovoid to slenderly obovoid, with 3–4 leaf primordia.............. 1. P. annotina
7. Leaf apices slenderly acuminate; costae slender, nearly percurrent to percurrent; gemmae elongate-obovoid or slenderly clavate to elongate-cylindrical, with 1–3 leaf primordia...............................................8
8. Plants usually branched; leaf margins more or less recurved; gemmae usually present, sometimes few, slenderly clavate to elongate-cylindrical, with short leaf primordia.......................................... 8. P. flexuosa
8. Plants simple; leaf margins plane; gemmae elongate-obovoid, with elongate leaf primordia.... 10. P. hisae
9. Plants with knobby gemmae on rhizoids.............................................................17. P. lutescens
9. Plants without gemmae on rhizoids.........................................................................10
10. Stems slender, nearly leafless on the lower part; capsules reddish.........................2. P. atrothecia
10. Stems often stout, at least with leaves sparsely located on the lower part; capsules not reddish............. 11
11. Median leaf cells broad, usually more than 12 µm wide........................................12
11. Median leaf cells narrow, usually less than 12 μm wide........................................14
12. Leaves ovate-lanceolate to shortly lanceolate; leaf cells rhombic............................... 25. P. wahlenbergii
12. Leaves elongate-lanceolate or linear-lanceolate; leaf cells elongate-rhomboidal.................................... 13
13. Leaf apices acuminate, scarcely denticulate; costae percurrent; median leaf cells 12–19 μm wide....... 9. P. gedeana
13. Leaf apices narrowly acute, distinctly denticulate; costae ending clearly below the apex; median leaf cells 16–28 μm wide.................................................................................. 23. P. tapintzensis
14. Plants very glossy; leaves stiff, straight when dry; rhizoids dense............................................15
14. Plants not glossy or slightly glossy; leaves not straight when dry; rhizoids few........................................ 20
15. Peristome teeth hyaline, smooth..............................................................11. P. hyaloperistoma
15. Peristome teeth yellowish, clearly papillose......................................................................16
16. Leaf bases more or less hyaline; capsules erect, cylindrical............................20. P. orthocarpula
16. Leaf bases not hyaline; capsules inclined to cernuous, pyriform or elongate-pyriform........................... 17
17. Leaves oblong-ovate to ovate-lanceolate, lower leaves small, ovate, becoming narrower and longer above, slightly contorted and slender at apex......................................................4. P. cruda
17. Leaves slenderly lanceolate, not much differentiated between lower and upper leaves, not contorted and slender at apex.................................................................................................18
18. Leaves oblong-lanceolate; leaf margins slightly serrulate near apex; dorsal surface of costae with spines
...........................................................................................12. P. laticuspis
18. Leaves linear-lanceolate; leaf margins clearly serrulate near apex; dorsal surface of costae smooth.... 19
19. Plants medium-sized, very stiff; leaves oblong-lanceolate, slenderly acuminate, not keeled at apex..............
.............................................................................................. 5. P. crudoides
19. Plants large, somewhat stiff; leaves linear-lanceolate, cuspidate or keeled at apex.........24. P. timmioides
20. Leaves sparse on stems...........................................................................................21
20. Leaves dense on stems............................................................................................23
21. Plants large; capsules long-clavate, usually 7.0 mm long when mature.................18. P. macrocarpa
21. Plants medium-sized; capsules nearly pyriform, usually less than 5.0 mm long when mature.............22
22. Plants occur on roadsides or forest grounds (gemmae sometimes present).......................... 8. P. flexuosa
22. Plants restricted in bogs, usually associated with Sphagnum (gemmae absent)........... 22. P. sphagnicola
23. Leaves almost the same size throughout stems; capsules elongate-clavate, apophyses ca. 1/2 as long as or slightly more than 1/2 longer than urn..................................................................................24
23. Leaves becoming larger upward; capsules ovoid, shortly cylindrical or nearly pyriform; apophyses clearly longer than urn................................................................................................................25
24. Plants dark green, not glossy; spores mammillose or minutely papillose.............................. 7. P. elongata
24. Plants yellowish green, glossy; spores clearly papillose................................15. P. longicollis
25. Capsules ovoid to shortly pyriform..............................................................13. P. lescuriana
25. Capsules nearly pyriform to shortly cylindrical..............................................19. P. nutans