1. Leaves without costa............................................................................................. 25. F. hyalinus
1. Leaves with costa.................................................................................................................................................... 2
2. Plants minute, budlike with very short stems.................................................................................................. 3
2. Plants larger, with distinct elongate stems...................................................................................................... 4
3. Protonema persistent; costa very weak, lacking on lower leaves; cells of apical laminae 23–35(–45) µm long; calyptra smooth, ...................................................................................................... 41. F. protonematicola
3. Protonema not persistent; costa distinct; cells of apical laminae 13–17(–21) µm long; calyptra distinctly
4. Leaves soft; cells of apical laminae lax and large, 19–50 µm long............................................................... 5
4. Leaves more or less firm; cells of apical laminae dense, usually not more than 20 µm long, or if longer, the upper end of vaginant laminae extremely unequal.................................................................................... 6
5. Leaves densely arranged to the base of stems, without limbidia or weakly bordered by 1–2 rows of elongate cells (often submarginal)...................................................................................4. F. bogoriensis
5. Leaves laxly arranged, at least not densely arranged to the base of stems, with distinct limbidia all around the margins......................................................................................................16. F. flaccidus
6. Leaves at least partially limbate...........................................................................................................7
6. Leaves not limbate........................................................................................................................... 29
7. Limbidia all around the leaf margins ................................................................................................... 8
7. Limbidia confined to the vaginant laminae or present only on vaginant laminae of perichaetial leaves....... 16
8. Capsules curved, asymmetrical........................................................................................................................ 9
8. Capsules straight to nearly straight, symmetrical ....................................................................................... 10
9. Leaves lanceolate to narrowly lanceolate; upper end of vaginant laminae open to costa (extremely unequal); cells of apical laminae 17–35 µm long........................................................................................... 3. F. beckettii
9. Leaves oblong‑lanceolate to ovate‑lanceolate; upper end of vaginant laminae equal to slightly unequal; cells of apical laminae 7–14 µm long................................................................................................... 50. F. tosaensis
10. Laminal cells with a small papilla in center.................................................................... 1. F. angustifolius
10. Laminal cells smooth................................................................................................................................... 11
11. Cells at base of vaginant laminae up to 42 µm long, much longer than those of apical and dorsal laminae
(9–21 µm long); axillary hyaline nodules well differentiated........................................................................ 12
11. Cells at base of vaginant laminae up to 21 µm long, only slightly longer than those of apical and dorsal laminae (5–14 µm long); axillary hyaline nodules not or weakly differentiated.......................................... 13
12. Leaves lanceolate, synoicous............................................................................................. 52. F. zollingeri
12. Leaves narrowly lanceolate, rhizoautoicous................................................................. 46. F. subbryoides
13. Sterile and fertile stems often differentiated; inflorescences rhizoautoicous; perichaetial leaves much larger than lower leaves................................................................................................................ 12. F. curvatus
13. Sterile and fertile stems undifferentiated; inflorescences various; perichaetial leaves not well differentiated from lower stem leaves ............................................................................................................. 14
14. Limbidia weak to relatively distinct, usually colorless; base of dorsal laminae not decurrent........ 5. F. bryoides
14. Limbidia usually distinct on apical laminae, yellowish on older leaves; base of dorsal laminae more or less decurrent, or not decurrent............................................................................................................ 15
15. Plants 5–15 mm high; leaves 1.8–2.5 mm long; setae 2.5–5.0(–10.0) mm long, lateral or terminal; antheridia 120–170 µm long..................................................................................................... 32. F. longisetus
15. Plants smaller, not more than 10 mm high; leaves 1.4–1.6 mm long; setae 3.5–4.0 mm long; antheridia (190–) 210–340 µm long ................................................................................................................ 20. F. geppii
16. Leaf cells and exothecial cells distinctly unipapilllose .................................................. 6. F. capitulatus
16. Leaf cells variously papillose or smooth, exothecial cells smooth ...................................................... 17
17. Laminal cells smooth......................................................................................................................................... 18
17. Laminal cells papillose ..................................................................................................................................... 20
18. Setae only 0.4–0.8 mm long; capsules usually immersed in upper leaves, urns 0.7–0.8 mm long; dioicous or rhizoautoicous............................................................................................... 47. F. subsessilis
18. Setae more than 2.0 mm long; capsules well exserted above the upper leaves, urns 0.4–0.65 mm long; autoicous...................................................................................................................................................... 19
19. Central strand not differentiated; upper leaves oblong-ovate, 1.2–1.5 mm long, acute or obtusely acute at apex; costa ending below the apex; vaginant laminae 2/3 –4/5 the leaf length..................... 13. F. diversifolius
19. Central strand weakly differentiated; upper leaves lanceolate to narrowly lanceolate, 1.75–2.30 mm long, narrowly acute at apex; costa percurrent to shortly excurrent; vaginant laminae 1/2 – 2/3 the leaf length..............42. F. schusteri
20. Leaf cells with 1 (rarely 2) small papillae ............................................................................................... 21
20. Leaf cells pluripapillose............................................................................................................................. 22
21. Upper leaves oblong lanceolate, acute at apex; cells of apical laminae quadrate to hexagonal, 9–21 µm long, slightly mammillose with 1 (rarely 2) small, indistinct papillae, thin-walled.............. 43. F. schwabei
21. Upper leaves lanceolate, narrowly acute at apex; cells of apical laminae irregularly rounded hexagonal, 3.5–9.0 µm long, highly mammillose with 1 (rarely 2) distinct papillae, moderately thick-walled...... 10. F. crenulatus
22. Setae more or less scabrous; perigonia in axils of leaves................................................ 24. F. hollianus
22. Setae always smooth; perigonia terminal on short branches at the base of female stems (if perigonia in axils of leaves, limbidia submarginal) .................................................................................................. 23
23. Leaves densely overlapping to base; upper leaves narrowly lanceolate or linear‑lanceolate ..................... 24
23. Leaves laxly arranged near base; upper leaves oblong‑lanceolate to lanceolate........................................... 26
24. Axillary hyaline nodules indistinct; limbidia weak, found only on lower half of vaginant laminae of upper and perichaetial leaves..................................................................... 31. F. linearis var. obscurirete
24. Axillary hyaline nodules well or weakly differentiated; limbidia found on vaginant laminae of almost every leaf ..................................................................................................................................................... 25
25. Axillary hyaline nodules well differentiated; rhizoautoicous; fertile and sterile stems differentiated and connected at base; setae terminal on short female stems................................................ 30. F. kinabaluensis
25. Axillary hyaline nodules weakly differentiated; autoicous; fertile and sterile stems not differentiated; setae terminal on stems............................................................................................................... 51. F. wichurae
26. Leaf cells highly mammillose, with a cluster of 2–5 high papillae at center............... 26. F. incognitus
26. Leaf cells not visibly mammillose, with papillae along the cell walls................................................... 27
27. Leaf apices acute; costa percurrent to shortly excurrent....................................................... 7. F. ceylonensis
27. Leaf apices rounded to obtuse; costa ending below leaf apex ....................................................................... 28
28. Vaginant laminae unequal; the minor laminae narrowed distally, ending on or very close to the costa; peristome teeth erect when wet, undivided or incompletely divided .............................. 18. F. gardneri
28. Vaginant laminae more or less equal; the minor laminae acute, ending on or very close to the leaf margins; peristome teeth inflexed when wet, divided more or less 2/3 their length ......... 33. F. minutus
29. Several rows of cells at margins of apical laminae lighter in color and smooth, markedly differentiated from inner cells as a paler band......................................................................................................................... 30
29. Marginal cells not as above, usually not differentiated from inner cells, or if differentiated, then only 1–2 rows of cells, or darker in color due to multi‑stratose cells ......................................................................... 31
30. Leaves lanceolate; costa percurrent, paler margins 3–4 cells wide; cross section of apical laminae 1–2 cells thick; setae 5–8 mm long............................................................................................. 14. F. dubius
30. Leaves narrowly lanceolate; costs excurrent, paler margins 1–3 cells wide; cross section of apical laminae 1 cell thick; setae not more than 2 mm long......................................................... 2. F. anomalus
31. Leaf margins dark in color, 2– 4 cells thick ................................................................................................... 32
31. Leaf margins not differentiated from other laminal cells .............................................................................. 34
32. Axillary hyaline nodules well differentiated; base of dorsal laminae rounded............. 28. F. javanicus
32. Axillary hyaline nodules not differentiated; base of dorsal laminae wedge‑shaped.............................. 33
33. Plants smaller, stems 8–11 mm long; leaf apices crenulate or nearly entire; leaf margins 2 cells thick; base of dorsal laminae not decurrent......................................................................... 29. F. jungermannioides
33. Plants larger, stems 18–60 mm long; leaf apices irregularly dentate; leaf margin 2–4 cells thick; base of dorsal laminae decurrent................................................................................................................. 34. F. nobilis
34. Plants aquatic; leaf bases distinctly decurrent on stems.......................................................................... 35
34. Plants not aquatic; leaf bases not distinctly decurrent on stems............................................................. 37
35. Leaves more or less crispate when dry; apical laminae 1 cell thick; costa clearly defined; with 1 row of irregularly quadrate to rectangular, smooth, more or less pellucid cells along both sides of costa............... 19. F. geminiflorus
35. Leaves almost straight when dry; apical laminae 1–6 cells thick; costa obscure; cells along both sides of costa not different from other laminal cells................................................................................................... 36
36. Leaves translucent under microscope; apical laminae 1–4 cells thick; two rows of rectangular guide cells visible through surface cells from middle to upper portion of costa............ 39. F. perdecurrens
36. Leaves not translucent under microscope; apical laminae 1–6 cells thick; two rows of guide cells not visible as above................................................................................................................ 21. F. grandifrons
37. Plants very small, leafy stems only 0.8–1.7 mm long; margins of vaginant laminae more or less distinctly serrate.................................................................................................................................................................. 38
37. Plants small to larger, leafy stems usually more than 3 mm long; margins of vaginant laminae almost entire to serrulate or crenulate.......................................................................................................................... 39
38. Margins of vaginant laminae evenly serrate; cells of apical laminae smooth.............. 15. F. flabellulus
38. Margins of vaginant laminae irregularly and sharply serrate; cells of apical laminae distinctly papillose......44. F. serratus
39. Axillary hyaline nodules very prominent.......................................................................................................... 40
39. Axillary hyaline nodules not well differentiated ............................................................................................. 42
40. Cells of apical laminae multipapillose......................................................................... 45. F. subangustus
40. Cells of apical laminae mammillose......................................................................................................... 41
41. Central strand not differentiated; leaf apices widely acute; costa percurrent or ending a few cells below apex
............................................................................................................................. 11a. F. crispulus var. crispulus
41. Central strand weakly differentiated; leaf apices narrowly acute; costa shortly excurrent..............................
........................................................................................................................... 11b. F. crispulus var. robinsonii
42. Cells of vaginant laminae with 3–4 papillae at corners ......................................... 49. F. teysmannianus
42. Cells of vaginant laminae not papillose at corners................................................................................... 43
43. Cells of apical laminae smooth or slightly mammillose................................................................................ 44
43. Cells of apical laminae papillose or distinctly mammillose.......................................................................... 49
44. Plants small; leafy stems 1.4–9.0 mm long.............................................................................................. 45
44. Plants medium‑sized to large; leafy stems 18.0–72.0 mm long ............................................................ 48
45. Costa ending 6–9 cells below the leaf apex................................................................. 22. F. guangdongensis
45. Costa percurrent to shortly excurrent............................................................................................................... 46
46. Costa usually curved above the vaginant laminae; the dorsal laminae slightly decurrent at the base; leaf cells rather thin‑walled............................................................................................... 17. F. ganguleei
46. Costa more or less straight above the vaginant laminae; the dorsal laminae not decurrent; leaf cells more or less thick-walled .......................................................................................................................... 47
47. Leaves lanceolate; cells of apical laminae moderately thick-walled, 10–24 µm long; synoicous (polyoicous)....................
............................................................................................................................................................. 38. F. pellucidus
47. Leaves lanceolate to narrowly lanceolate; cells of apical laminae thick- to very thick-walled, lumen 8–13 µm long; dioicous...................................................................................................................... 9. F. crassinervis
48. Leaf apex mostly mucronate, rarely obtusely acute; cells of apical laminae 11–21µm long, walls clear............................................................................................................................................40. F. polypodioides
48. Leaf apex obtusely acute; cells of apical laminae 10–13 µm long, walls obscure......... 36. F. obscurus
49. Setae lateral or basal; perichaetial leaves much smaller than stem leaves............................. 48. F. taxifolius
49. Setae terminal; perichaetial leaves not or indistinctly differentiated............................................................ 50
50. Plants larger, leafy stems 10–50 mm long, 2.0–5.0 mm wide; costa percurrent........... 27. F. involutus
50. Plants smaller, leafy stems 3–7 mm long, 2.5–3.0 mm wide; costa usually ending a few cells below leaf apex ...................................................................................................................................................... 51
51. Leaf apices narrowly acute or obtuse to obtusely acute................................................................................. 52
51. Leaf apices widely acute, often mucronate ..................................................................................................... 53
52. Apices of dry leaves often enrolled towards the substrate; apical laminal cells 8–14 µm long ..............
52. Apices of dry leaves often enrolled away from the substrate; apical laminal cells 5–8 µm long.............
53. Leaves lingulate to lanceolate; laminal cells distinctly mammillose, with indistinctly demarcated walls.....
......................................................................................................................23. F. gymnogynus
53. Leaves ovate‑oblong to ovate‑lanceolate; laminal cells more or less mammillose, with well demarcated walls...............................................................................................................37. F. osmundoides