Inversodicraea

Tchouto, P. & Burgt, X. van der, 2017, A synoptic revision of Inversodicraea (Podostemaceae), Blumea 62 (2), pp. 125-156 : 133-134

KEY TO SPECIES OF INVERSODICRAEA

1. Scale-leaves densely covering (by 50 % or more) both the principal stems and the side-branches (if any)........ 2

1. Scale-leaves only on the side-branches and/or absent to sparsely covering (<40 % cover) the principal stems.. 17

2. Scale-leaves entire or sometimes with 1(–2) shallow lateral lobes........................................ 3

2. Scale-leaves always 3–15-lobed or toothed, lobes usually deep (but covering <10 % of the leaflet length in I. congolana )......................................... 9

3. Scale-leaves linear-subulate. — Sierra Leone 1. I. mortonii

3. Scale-leaves ovate, orbicular, or obovate, apex dentate, lobed or rounded............................... 4

4. Scale-leaves longer than wide, often with 1–2 shallow lateral lobes........................................ 5

4. Scale-leaves orbicular or ovate, unlobed. — Gabon...................................... 3. I. boumiensis

5. Scale-leaves ± patent or spreading, covering c. 50 % of the stem, sometimes with 1–2 side lobes........... 6

5. Scale-leaves ± appressed to the stem, covering 70–100 % of the stem, lacking side lobes................... 7

6. Flowers with 1 stamen, fruit with 8 ribs. — Guinea..................................... 23. I. pepehabai

6. Flowers with 2 stamens, fruit with 6 ribs. — Liberia........................................ 30. I. liberia

7. Scale-leaves broadest in the distal half, apex broadly convex. — Cameroon........... 17. I. kamerunensis

7. Scale-leaves broadest in the proximal half, tapering towards a slender apex................................ 8

8. Flower with 1 stamen; scale-leaves on proximal third of principal stem more than twice as long as broad. — Gabon, Congo.......................... 2. I. gabonensis

8. Flower with 2 stamens; scale-leaves on proximal third of the stem more than twice as long as broad. — Gabon.....................................19. I. thollonii

9. Scale-leaves digitately 5–15-lobed or toothed...... 10

9. Scale-leaves 3(–4)-lobed...................... 14

10. Apex of leaflet lobes rounded; stamen 1. — Angola....................................... 4. I. digitata

10. Apex of leaflet lobes acute; stamens 2 (where known) 11

11. Scale-leaves, in addition to the marginal teeth or lobes bearing 4–10 spines on abaxial surfaces. — Cameroon................................... 26. I. xanderi

11. Scale-leaves teeth or lobes on margin only, projections absent from abaxial surfaces................... 12

12. Leaflet lobes 8–14, tine-like; ovary and fruit apex winged. — Cameroon.......................... 25. I. ebo

12. Leaflet lobes 5–11, triangular; ovary and fruit without wings ........................................... 13

13. Scale-leaves about as long as wide, scale-leaves at stem base tridentate, pedicels 5–10 mm long in fruit. — Cameroon, C.A.R.......................... 5. I. cristata

13. Scale-leaves twice as long as wide, scale-leaves at the stem base entire, rounded; pedicels 14–15 mm long in fruit. — Cameroon................... 28. I. tchoutoi

14. Scale-leaves flat with only 3 straight lobes at apex... 15

14. Scale-leaves not flat, the 3 apical lobes curved inwards, and a fourth curved, reflexed lobe on the abaxial surface. — Guinea, Sierra Leone............ 7. I. harrisii

15. The three lobes triangular, subequal.............. 16

15. The three lobes linear, the central lobe twice as long as the two lateral lobes. — Guinea......... 8. I. pygmaea

16. Leaflet oblong, the lobes minute, apical, occupying only c. 10 % of the length of the leaflet and shorter than the width of the unlobed part of the leaflet.. 6. I. congolana

16. Leaflet palmate in outline, the lobes occupying 40–50 % of the length of the leaflet, and longer than the width of the unlobed part of the leaflet. — Guinea to Angola....................................... 9. I. ledermannii

17. Principal stems> 20 cm long, lax, flowing in the water and lacking scale-leaves; scale-leaves dense on spur shoots <1 cm long................................. 18

17. Principal stems either <20 cm, and/or erect, and/or with at least some scale-leaves present............... 21

18. Principal stems unbranched along their length...... 19

18. Principal stems with several major branches along their length...................................... 20

19. Scale-leaves broadly elliptic, finely denticulate. — Gabon............................... 10. I. annithomae

19. Scale-leaves with three equal lobes. — Gabon, Congo..................................11. I. paulsitae

20. Apex of ovary and fruit with 6 short wings. — Angola................................. 12. I. warmingiana

20. Apex of ovary and fruit lacking wings. — Angola......................................... 13. I. fluitans

21. Principal stems> 20 cm long, flowing in water...... 22

21. Principal stems <20 cm long, usually 1–12 cm long, erect ........................................... 24

22. Fruits and ovary strongly laterally compressed, usually not in axils of pseudo-dichotomies.................. 23

22. Fruits and ovary terete (not compressed), usually single in axils of pseudo-dichotomies. — Cameroon......................................... 21. I. ntemensis

23. Scale-leaves subtending each spathellum c. 10, often with a lateral lobe; stigmas triangular. — Sierra Leone.......................................... 24. I. feika

23. Scale-leaves subtending each spathellum 1–2, entire, stigmas linear. — Ivory Coast........ 27. I. cussetiana

24. Scale-leaves with projections on the abaxial surface. — Tanzania to Botswana.................. 14. I. tenax

24. Scale-leaves without projections on the abaxial surface ........................................... 25

25. Scale-leaves needle-like, not lobed (but with two short lateral lobes at stem apex with spathellae). — Guinea.................................... 15. I. abbayesii

25. Scale-leaves triangular, ovate, or oblong, apex entire or lobed...................................... 26

26. Plants 1(–2) cm tall, scale-leaves ± uniformly equilaterally triangular, not lobed. — Cameroon.. 22. I. achoundongii

26. Plants> 2 cm tall, scale-leaves ovate, oblong, sometimes lobed...................................... 27

27. Scale-leaves mostly (90 %) ovate, entire (near spathellae slightly lobed). — Cameroon.............. 16. I. bosii

27. Scale-leaves not ovate, but oblong, broadly or narrowly, and lobed................................... 28

28. Scale-leaves as long as broad, or slightly longer (near spathellae needle-like), ovary apex winged. — Cameroon................................ 29. I. eladii

28. Scale-leaves twice to four times longer than broad, ovary apex unwinged.............................. 29

29. Scale-leaves about twice as long as broad, ovary and fruit 6-ribbed. — Guinea, Sierra Leone...... 20. I. adamesii

29. Scale-leaves about four times as long as broad, ovary and fruit 8-ribbed. — Mozambique.............18. I. torrei