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