Podostemaceae
 
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KEY TO THE GENERA OF AFRICA

 

 

1. Tepals 2 or occasionally 3 or 4, not imbricate, restricted to one side of the flower, linear to subulate; young flowers totally enclosed in a spathella (a sack-like cover); capsules opening by 2 valves

- Tepals 3, imbricate, surrounding the young flowers, ovate to oblong-obovate; young flowers not enclosed in a spathella; capsules opening by 3 valves (widespread in Africa & Madagascar)

 

2


2. Tristicha

2. Stigma 1, semi-globose; stamens 3 or rarely 4, united only at the base (Angola)

- Stigmas 2, linear, horn-like, or flattened and lobed; stamens 1, 2 or rarely 3, when 2 or 3 then borne on an elongate andropodium

 

24. Angolaea

3

3. Flowers erect or rarely slightly inclined within the unruptured spathellas

- Flowers inverted or strongly inclined within the unruptured spathellas

 

13

4

4. Tepals 2, 1 each side of the andropodium base, without an appendage between the stamens

- Tepals 3, 1 each side of the andropodium base and 1 borne terminally on the andropodium between the stamens

 

6

5

5. Capsules broadly ellipsoidal; capsule valves with 5 or 7 narrow ribs, those closest to the sutures not reaching the base and the apex (tropical W Africa)

- Capsules obovoid; capsule valves with 3 wide ribs, each extending from base to apex (Madagascar)

 

36. Stonesia


37. Thelethylax

6. Capsules smooth, globose or subglobose (Cameroon, D.R. Congo, Zambia)

- Capsules with longitudinal ribs or wings, laterally flattened or cylindrical to ellipsoidal or globose

 

30. Leiothylax

7

7. Ovaries and capsules terete, not flattened; capsules without winged nerves

- Ovaries and capsules flattened; capsules with or without winged nerves

 

9

8

8. Capsules strongly flattened, with winged middle nerves; wings longer than the capsule and forming apical horns;
stamens 2 (Cameroon)

- Capsules slightly to strongly flattened, without wings or apical horns; stamens 1, 2 or 3 (tropical W Africa)

 

38. Winklerella


32. Macropodiella

9. Capsules ovoid-ellipsoidal or partly cylindrical

- Capsules globose or subglobose

 

11

10

10. Pedicels less than 5 mm long; capsules sessile or borne on minute gynophores; stamen 1 or perhaps sometimes 2; pollen shed in dyads (Madagascar, tropical & South Africa)

- Pedicels up to 15 mm long; capsules borne on up to 8 mm long gynophores; stamens 2 or rarely 3; pollen shed in monads (Cameroon)

 

35. Sphaerothylax


39. Zehnderia

11. Flowers or flower clusters arranged in one row along the shoot; andropodium usually less than 1 mm long; stigmas conical, erect, rigid; capsules cylindrical to oblong (W & C Africa)

- Flowers or flower clusters arranged around the shoot, rarely in a row; andropodium usually much exceeding 1 mm long; stigmas linear, spreading or reflexed, flexible; capsules obovoid to ovoid or fusiform 12

 

26. Dicraeanthus


12

12. Capsule valves with 3 narrow or occasionally crest-like ribs; capsules ovoid to ellipsoidal or fusiform (species rich and widespread in tropical Africa)

- Capsule valves with 3 wide and flattened ribs; capsules obovoid (Madagascar)

 

29. Ledermanniella


37. Thelethylax

13. Capsule valves equal, usually both persistent; capsule sutures centric

- Capsule valves somewhat unequal, one valve caducous, the other persistent on pedicel or gynophore; capsule sutures acentric and oblique

 

15

14

14. Stamen 1; capsules globose or subglobose; capsule valves with 3 wide ribs, each extending from base to apex (Cameroon)

- Stamens 2, borne on an andropodium; capsules asymmetrically ovoid and somewhat laterally flattened; capsule valves with 7 narrow ribs, those closest to the sutures not reaching the base and the apex (Madagascar)

 

27. Djinga


28. Endocaulos

15. Capsules globose or subglobose, smooth and shiny (W Africa from Namibia to Niger)

- Capsules ovoid to ellipsoidal or fusiform, with longitudinal ribs

 

31. Letestuella

16

16. Flowering stems covered with at least 8 but usually many more, overlapping, scale-like leaves; stamens 2, borne on an andropodium (Madagascar)

- Flowering stems with elongate, simple or forked leaves or if leaves scale-like then rarely more than 4; stamen 1

 

33. Paleodicraeia


17

17. Leaves below the flowers scale-like, shorter than the flowers; capsules ovoid, laterally flattened; stigmas unequal, flattened, elliptic to ovate in outline (Nigeria)

- Leaves below the flowers linear or divided into linear segments, longer than the flowers; capsules elliptic to fusiform, terete; stigmas equal, linear (tropical W Africa)

 

25. Butumia


34. Saxicolella

 
       
    Copyright Institute of Systematic Botany, University of Zurich