Key E: Key to the 26 species of Ledermanniella subgenus Ledermanniella

(according to Taylor 1954; Cusset 1983, 1984, 1987; Ameka et al. 2003; Cheek 2003; Schenk & Thomas 2004; combined and modified by R. Rutishauser)

1. Leaves all short, scale-like or boat-shaped or if leaves conspicuous (> 3 cm long and often forked), at least bracts below flowers hood-like (i.e. provided with intrapetiolar stipule) giving rise to thread-like blade on dorsal side 2

-- Leaves neither boat-shaped nor hood-like, stipules (if present at all) 2 lateral ones, attached to leaf base (never 1 intrapetiolar stipule per leaf); leaves (blades) usually conspicuous, entire and elongate, or forked few to many times, with linear to thread-like segments; stamens 1, 2 or 3 6

2. All leaves short, boat-shaped (laterally flattened), arranged in 2 dense rows (distichous); elongate blades and stipules lacking; stamens 2 3

-- Leaves with hood-like (cupuliform) sheath (i.e. with intrapetiolar stipule) and filamentous, inconspicuous blades (1 - 8 mm long, rarely bifid) arising from dorsal side; elongate main stems present and up to 5 (?) cm long or absent; sessile flowers along stems and on upper surface of foliose root; stamens 1 or 2 4

3. Stems only 2 - 3 mm long, with solitary terminal flower each; or with solitary flowers sessile on foliose root L. aloides (Engler) C. Cusset [Angola; Cameroon: Tschape Pass - Adamaoua; Sierra Leone]

-- Stems (2-)5 - 7 cm long; leaves stiff, laterally flattened, 5 - 8(-10) mm long; solitary flowers, with a boat-shaped prophyll each, inserted in leaf axils L. onanai Cheek [Cameroon SW: Chide River]

-- Stems c. 6 cm long (check) , with densely arranged boat-shaped leaves; spathella lateral dehiscence (i.e. similar to L. onanai ) L. keayi (G. Taylor) C. Cusset [Cameroon: Bamenda, Kumbo]

4 . Leaf sheaths hood-like (see footnote 1) but incised apically into 2 stipular appendages (This hood-like sheath is identical (homologous) to a bifid intrapetiolar stipule. Such stipules also occur in L. bowlingii [Cameroon], in combination with 1 stamen per flower, pollen in dyads and ribbon-like roots (see this key below, and Ameka et al. 2003).); stems up to 5 (?) cm long; flowers restricted mainly to shoot tips; stamens 2; pollen in dyads L. batangensis (Engler) C. Cusset [Cameroon: Lobé Falls - Grand Batanga]

-- Leaf sheaths (especially bracts below flowers) hood-like and not incised apically, with dorsally inserted thread-like blade (entire or forked once); pollen in monads 5

5. Slender shoots (9 - 13 cm tall) with foliage leaves up to 4 (20?) cm long and forked several times into thread-like segments; flowers along stem and inserted in angles of stem forks or leaf forks (Check if L. prasina really with flowers arising from leaf forks (see footnote 2), i.e. epiphyllous from sites where leaf blade is forked (similar to L. letouzeyi , see Rutishauser 2004); stamens 1 (rarely 2) L. prasina J. Schenk & D. W. Thomas [Cameroon]

-- Shoots with stout stems (if present at all); forked foliage leaves along stem lacking (or not known); flowers on foliose root or sessile along stem; stamens 2 L. thalloidea (Engler) C. Cusset [Cameroon: Sanaga, Bipindi]

6 . Most leaves entire and elongate 7

-- Leaves compound, at least those next to flowers 18

7. Plants without stems (or with stems less than 1 cm long) 8

-- Plants with conspicuous stems (usually much more than 1 cm long) 12

8. Leaves arranged in rosettes (not restricted to 2 rows); roots foliose or ribbon-like 9

-- Leaves along two rows (distichous), arising on upper surface of foliose roots 10

9. Roots ribbon-like; leaves linear, 2 mm long, without broadened base; stamen 1; stigmas linear L. minutissima C. Cusset [Sierra Leone]

-- Roots foliose; leaves linear to subulate, 3 - 5 mm long, with suddenly broadened sheath; stamens 2; stigmas very short L. tenuifolia (G. Taylor) C. Cusset [Gabon; Nigeria; Cameroon?]

10. Leaves narrow linear to filamentous, occasionally with 2 lateral stipules, but without broad enclosing sheath; filamentous blade 1.5 cm long, as long as flower in anthesis; stamens 2; roots foliose L. linearifolia Engler [Cameroon: Campo, Lobé, Sahé]

-- Leaves with broad enclosing sheath; leaf blade shorter than the flower in anthesis 11

11. Leaves stipulate, with narrow linear blade, 2 - 4 mm long L. sanagaensis C. Cusset [Cameroon: Sanaga Falls]

-- Stems only 2 - 3 mm long; leaves very short (0.1 - 0.8 mm), boat-shaped (see footnote 3) or trifid (see footnote 4) with 2 stipular teeth and subulate blade, with solitary terminal flower each; or with solitary flowers sessile on foliose root L. aloides (Engler) C. Cusset [Angola; Cameroon: Tschape Pass - Adamaoua; Central African Republic; Sierra Leone]

12 . Leaves mainly towards the shoot tips, or arising from the angles of bifurcating stems 13

-- Leaves arranged along the whole stem length (at least leaf scars observable) 14

13. Leaves linear, with progressively broadened base; spathellas dehiscing from top L. ramosissima Hauman ex C. Cusset [Uganda]

-- Leaves boat-shaped and densily arranged along 2 rows (distichous); spathellas dehiscing with lateral slits L. keayi (G. Taylor) C. Cusset [Cameroon: Bamenda, Kumbo] (see footnote 5)

14. Leaves at least 2 - 4 cm long (often much longer, up to 30 cm,(see footnote 6), usually entire and sword-like (ensiform) with few to several parallel veins; roots as broad ribbons (up to 5 mm wide) L. letouzeyi C. Cusset [Cameroon: Ure - Mts Rumpi]

-- Leaves usually less than 2 cm long, neither ensiform nor provided with parallel nervature 15

15. Stamen 1 16

-- Stamens 2 or 3; leaves distichous; spathella with lateral dehiscence 17

16. Leaves filiform, 3 - 5 mm long, with narrow base, devoid of stipules; stamen shorter than the ovary; pollen in dyads L. jaegeri C. Cusset [Sierra Leone]

-- Leaves triangular, 1 - 2 mm long, or with blade (see footnote 7) up to 10 mm long, broad sheath provided with 2 stipules; stamen as long or longer than the ovary; pollen in monads L. monandra C. Cusset [Cameroon: Mayo Bika - Tignère]

17. Shoots heterophyllous; basal leaves short (3 - 5 mm), leaves below flowers linear, 10 -15 mm long; stamens 2, shorter than ovary L. musciformis (G. Taylor) C. Cusset [Cameroon: Bamenda, Tchampa]

-- All leaves similar, 3-4 mm long, densily arranged, with inrolled margins; stamens 2 or 3, as long or longer than ovary L. raynaliorum C. Cusset [Cameroon: Massif du Vokré; Nigeria]

18 . Stamen 1 (rarely 2 in L. prasina ) 19

-- Stamens 2 - 3(-4) 22

19. Stems 5 - 8 mm high; leaves forked once or twice, with deciduous linear segments; pollen in dyads L. pygmaea (Pellegrin) C. Cusset [Gabon]

-- Stems usually more than 2 cm long 20

20. Roots as ribbons, 1 - 4 mm wide, branched exogenously; stems up to 120 cm long; leaves up to 15 cm long, usually forked 3 - 7 times with thread-like segments, provided with 2 intrapetiolar stipules (basal leaves may be thread-like, entire or bifid); flowers along stems or root-born; pollen in dyads; stigmas conical (only 0.5 mm long), the two lobes with common cushion-like base L. bowlingii (J.B. Hall) C. Cusset [Ghana] (see footnote 8)

-- Roots foliose, pollen in monads; stigmas linear, not fused at base 21

21. Stems long and slender, 30 - 100 cm long; leaves 4 - 6 cm long, forked several times into thread-like and deciduous segments; flowers in stalked clusters (bracts lacking); stigmas linear (c. 1 mm long) with entire apices L. guineensis C. Cusset [Guinea]

-- Main stems up to 3 cm; s lender secondary shoots (9 - 13 cm tall) with foliage leaves up to 4 (20?) cm long and forked several times into thread-like segments; flowers along stem and inserted in angles of stem forks or leaf forks (see footnote 9), subtended by few hood-like bracts with inconspicuous thread-like blade arising from dorsal side (see footnote 10); stamens 1 (rarely 2); stigmas linear, each one with a bifid apex L. prasina J. Schenk & D. W. Thomas [Cameroon]

22 . Stems simple and less than 1 cm long; leaves entire and linear or forked; leaves below flowers usually with 2 attached lateral stipules; capsules with 1 valve caducous and one valve persistent 23

-- Stems more than 1 cm long, often up to 15 - 25 cm long; capsule valves caducous or persistent Go on with subkey 25 or subkey 29

23. Stigmas short (< 0.5 mm), dentate or with three lobes; stamens 2 - 3(-4) with filaments longer than common stalk (andropodium); leaves 5 - 10 mm long, entire and linear or bifid, with broad sheath, occasionally provided with two lateral stipules; flowers solitary or in clusters of 2 (- 7) at shoot tips L. variabilis (G. Taylor) C. Cusset [Cameroon: Lobé, Munaya - Mamfe]

-- Stigmas linear (0.6 - 0 .7 mm); stamens 2 with common stalk usually longer than free filaments; leaves 0.7 - 6 cm long, entire and linear, or forked up to 3 times into linear segments 24

24. Stems (if short) with solitary flower in terminal position; pollen in monads (also dyads? see footnote 11) L. bifurcata (Engler) C. Cusset [Cameroon: Bipindi, Lobé, etc.; Congo; Gabon]

-- Stems always short (up to 1 cm) and with terminal clusters of up to 5 - 7 flowers, or shoots reduced to root-born rosettes with solitary terminal flower; pollen in dyads L. pusilla (Warming) C. Cusset [Cameroon: Lobé, Lokoundje; Gabon; Zaïre]

25 . Capsules with one valve caducous; stamens 2 or 3 26

-- Dehiscing capsules with both valves persisting on pedicel; stamens 2 28

26. Shoots 10 - 15 cm long, rarely branched; stalked flower clusters secund along the stems; stamens 2 or 3, with free filaments as long as common stalk (andropodium) ; stigmas very short; (pollen in monads or dyads? see footnote 12). L. boloensis C. Cusset [Gabon]

-- Shoots (if present at all) up to 20 cm long; flowers not secund along the stems; stamens 2, with free filaments much shorter than common stalk (andropodium); stigmas linear; pollen in monads (see footnote 13) 27

27. Leaves up to 25 mm long, entire and linear or forked up to 3 times into linear segments; some leaves with 2 attached lateral stipules L. bifurcata (Engler) C. Cusset [Cameroon: Bipindi, Lobé, etc.; Congo; Gabon]

-- Leaves up to 15 mm long, forked up to 6 times into thread-like segments; no stipules L. letestui (Pellegrin) C. Cusset [Gabon]

28. Main shoots 5 - 25 cm long, with sessile or stalked flower clusters secund (restricted to one sector) along the stems; pollen in monads L. nicolasii C. Cusset [Gabon]

-- Shoots up to 30 cm long; flowers often solitary in the angles of forked stems (see footnote 14) or in leaf axils but never secund; spathellas often stalked; pollen in dyads L. schlechteri (Engler) C. Cusset [Cameroon: Dehane, Edéa; Congo; Zaïre]

29 . Roots ribbon-like; elongate shoots often forked (branched dichotomously); solitary flowers or flower clusters in the angles of forked stems or in leaf axils along stems, but not secund 30

-- Roots foliose (crustaceous); elongate main shoots 5 - 25 cm long, with usually stalked flower clusters restricted to one side of the stem (i.e. secund) 32

30. Shoots up to 6 cm (?) long; stems relatively thick; leaves up to 25 mm long, entire and linear or forked up to 3 times into linear segments; at least some leaves with 2 attached lateral stipules; pollen in monads (also dyads? See footnote) L. bifurcata (Engler) C. Cusset [Cameroon: Bipindi, Lobé, etc.; Congo; Gabon]

-- Shoots (including stems) elongate and slender, up to 20 cm and lore, branched dichotomously (or seemingly so); leaves c. 3 (?) cm long, forked up to 6 times into thread-like segments; stipules lacking; flowers inserted in angles of stem forks 31

31. Shoots 4 - 20 cm long; flowers in sessile clusters in angles of stem forks (or along zig-zag stem); pollen in monads L. letestui (Pellegrin) C. Cusset [Gabon]

-- Shoots up to 30 cm long; flowers solitary in angles of stem forks (see footnote 15); pollen in dyads L. schlechteri C. Cusset [Cameroon: Dehane, Edéa; Congo; Zaïre]

32. Elongate shoots always with stalked flower clusters; (leaves unknown); stamens 2 or 3, with free filaments at least as long as common stalk (andropodium) ; (pollen in monads or dyads? (see footnote 16)); stigmas very short (c. 0.2 mm) L. boloensis C. Cusset [Gabon] (see footnote 17)

-- Elongate shoots with (occasionally sessile?) flower clusters; each flower cluster opposite to a foliage leaf; stamens 2; with free filaments shorter than common stalk (andropodium) ; pollen in monads; stigmas filiform (c. 0.7 mm) L. nicolasii C. Cusset [Gabon] (see footnote 18)

Footnotes

1 This hood-like sheath is identical (homologous) to a bifid intrapetiolar stipule. Such stipules also occur in L. bowlingii [Cameroon], in combination with 1 stamen per flower, pollen in dyads and ribbon-like roots (see this key below, and Ameka et al. 2003).

2 Check if L. prasina really with flowers arising from leaf forks, i.e. epiphyllous from sites where leaf blade is forked (similar to L. letouzeyi , see Rutishauser 2004).

3 See Engler (1930, Fig.46)

4 See Cusset (1984, 1987)

5 Check if this description also fits for recently described species L. onanai ...

6 See Rutishauser (2004)

7 According to Cusset (1997) leaf blade very short, only 0.4 - 0.6 mm (but see Engler 1930: Fig. 38: blade up to 10mm)

8 See Ameka et al. (2003) on comparative morphology of L. bowlingii

9 Check if L. prasina really with flowers arising from leaf forks, i.e. epiphyllous from sites where leaf blade is forked (similar to L. letouzeyi , see Rutishauser 2004).

10 See this key above

11 See Engler (1915, 1926, 1930: Fig.48 under synonym Inversodicraea minima )

12 Check! Not mentioned by Cusset (1984)

13 Engler found dyads in L. bifurcata (syn. Inversodicraea minima , see foot-note above)

14 This branching pattern with flowers or flower clusters arising from the angle of forked stems (or forked leaf lobes!) resembles similar patterns in L. letestui , L. letouzeyi , and L. prasina .

15 Closely resembling L. prasina ! Check if L. schlechteri and L. letestui really without (intrapetiolar) stipules! Similar to L. prasina it appears also difficult to decide in these two species where the forked stems continue into the forked leaves....

16 Check! Not mentioned by Cusset (1984)

17 L. boloensis resembles to some degree L. nicolasii and Macropodiella spp. (check if capsule really terete and one valve always caducous; these taxa are sympatric in Gabon). Check if L. boloensis is nothing but a badly collected form of L. nicolasii ... (leaves unknown, stigmas dropped to some degree).

18 L. nicolasii resembles to some degree L. boloensis and Macropodiella spp. (check if capsule really terete and both valves always persistent; these taxa are sympatric in Gabon)