1. Tepals 2 or occasionally 3 or 4, restricted to one side of the flower, linear to subulate, not imbricate; young flowers totally enclosed in a spathella (a sack-like cover); capsules opening by 2 valves or indehiscent; stamens 1 or 2, when 2 then borne on an andropodium; pollen shed as dyads

- Tepals 3, surrounding the young flowers, ovate to oblong-obovate, imbricate; young flowers not enclosed in a spathella; capsules opening by 3 valves; stamens 1--3, free; pollen shed as monads 2

4




2

2. Stems, at least partly elongate, bearing ramuli (moss-like branchlets with scale-like or linear appendages); roots elongate, thread-like or ribbon-like

- Stems, flattened, closely attached to substrate, crustose (foliose), without ramuli, often bearing photosynthetic scales above; roots absent or flattened and somewhat irregular in shape (S & SE Asia)

3

3. Dalzellia

3. Flowers borne on slender pedicels without cup-like structures at the base; stems variable, often creeping, when free then usually considerably less than 10 cm long; ramuli with scales arranged in 3 rows (China, Malaysia, Australia)

- Flowers arising from cup-like structures of united scales and ramuli; stems usually free, branched, up to 60 cm long; scales or linear appendages of ramuli arranged in many rows or irregularly scattered (S India)

2. Tristicha



4. Indotristicha

4. Leaves or scales on flowering stems all entire

- Leaves or scales on flowering stems with at least some divided into 2--8 simple lobes or lateral teeth

8

5

5. Leaves or scales on flowering stems arranged in 2 rows or appearing to be irregular

- Leaves or scales of flowering stems arranged in 4 or 6 neat rows

7

6

6. Capsule valves unequal, the larger persisting; 2 of the rows of leaves or scales on flowering stems with filamentous tips (SW India)

- Capsule valves equal; 2 of the rows of leaves or scales on flowering stems  2-lobed  (N Thailand)

48. Willisia


44. Hanseniella

7. Capsule valves equal; spathellas thick, with 2 or 3 ridges; stamens mostly 2, borne on an andropodium; leaves or scales on flowering stems mostly 3-lobed  (N Thailand)

- Capsule valves unequal; spathellas thin, without ridges; stamen mostly 1, simple; leaves or scales on flowering stems 2- to 8-lobed, rarely consistently 3-lobed  (E & SE Asia, New Guinea, NE Australia)

47. Thawatchaia


40. Cladopus

8. Capsule valves unequal, the smaller one caducous

- Capsule valves equal, usually both persisting or sometimes both caducous

11

9

9. Capsule valves each with 9 fine ribs (excluding the lateral sutures); capsules laterally flattened (Vietnam, Laos)

- Capsule valves each with 2--6 ribs (excluding the lateral sutures); capsules ± terete

41. Diplobryum


10

10. Roots crustose, closely attached to substrate; flowers usually subsessile, scarcely raised above the spathella at anthesis (E Himalaya, S China, E & SE Asia)

- Roots elongate (ribbon- or thread-like), with the distal part usually free and floating; flowers pedicellate, held well above the spathella at anthesis (Sri Lanka, India, Thailand)

45. Hydrobryum


46. Polypleurum

11. Flowers sessile or nearly so, usually remaining within the opened spathella or just emerging above it; pedicels not more than 1 mm long; shoots confined to the margins of elongate roots; stamen 1 (consistently so from flower to flower); stigmas unequal; capsules indehiscent or dehiscent; seeds 1--8 (--18) (S India, Sri Lanka)

- Flowers stalked or subsessile, emerging above the opened spathella; pedicels usually more than 1 mm long; flowering shoots developing from the upper surface of crustose (foliose) roots or in the sinuses of lobed, ribbon- or thread-like roots; stamens 2, borne on an andropodium or rarely 1 (usually some flowers with 2); stigmas equal; capsules dehiscent; seeds 12 to numerous

42. Farmeria




12

12. Capsules with prominent, longitudinal ribs (Sri Lanka, S, W & NE India, Myanmar)

- Capsules smooth or obscurely ribbed

49. Zeylanidium

13

13. Spathellas erect, funnel-shaped, splitting into several rather irregular apical teeth; roots irregular in form, varying from star- to cup-shaped or ribbon-like but not regularly pinnate (S India)

- Spathellas prostrate, boat-shaped, splitting longitudinally; roots ± regularly, pinnately branched (S India)

43. Griffithella



49. Zeylanidium