Marantochloa Brongn. & Gris.

Ley, Alexandra C. & Classen-Bockhoff, Regine, 2012, Five new species of Marantaceae endemic to Gabon, Adansonia (3) 34 (1), pp. 37-52 : 48-49

Marantochloa Brongn. & Gris.

This genus is widely distributed from Senegal to Madagascar and includes currently 17 species on the African mainland and one further species( M.comorensis Brongn. ex Gris ) described from Madagascar which is similar to M. filipes but with white-yellow flowers ( Perrier de la Bâthie 1946, but see also Catalogue of the Vascular Plants of Madagascar:http://www.tropicos.org/project/ mada).All species of Marantochloa are perennial herbs from 0.5 to 4 m in height.They are recognized by their characteristic leaf shape which is straight on one side and rounded on the other side with a slight displacement of the leaf tip versus the central vein ( Fig. 2 ). On the leaf underside along the rounded side there is often a differently coloured band. This particular shape allows the distinction between an anti- and a homotrop leaf positioning along the shoot. The reddish colouration on the underside of the leaf in some species is a highly variable character not useful for identification.

The star (*) between two species means that the first author does not agree with the distinction between these two taxa as proposed by Dhetchuvi (1996a, b). Characters described to distinguish the two species are highly variable and overlap between species and herbarium specimens (including types) did not show distinct sets of characters.

1. Plants with strictly one leaf per shoot ......................................................................... 2

— Plants with several leaves per shoot ............................................................................. 3

2. Inflorescence green, arising from upper part of the shoot near the leaf; flowers small (c. 1 cm), white; ovary and fruit yellow; restricted to Lower Guinea and Congolia .............................................................................................................. M. monophylla

— Inflorescence reddish, arising from the shoot a few centimetres above the ground; flowers large (20 mm long), white, in the centre violet and yellow; leaves long, lanceolate; ovary and fruit red/brownish; species so far only known from the Monts de Cristal ..... M. grandiflora

3. Leaves antitrop ........................................................................................................... 4

— Leaves homotrop ........................................................................................................ 7

4. Plant with 2 to 4 leaves per shoot ............................................................................... 5

— Plant multi-branched with numerous leaves per shoot ................................................ 6

5. Plants with 2 to 4 leaves; leaf lamina at base cordate; restricted to Lower Guinea........... .............................................................................................................. M. incertifolia *

— Plant with 3 leaves; leaf lamina less cordate; restricted to Gabon............ M. sulphurea *

6. Leaves small, 3.5-8.5 cm long, 1-4.5 cm wide; endemic to Mont de Chaillu in Gabon.. .............................................................................................................. M. microphylla

— Leaves larger, 8-20 cm long, 3-10 cm wide; conspicuously hairy above callous; widespread .................................................................................................................. M. congensis

7. Inflorescence lax, ± hanging; internodes 15-30 mm .................................................... 8

— Inflorescence dense, erect; internodes <15 mm ........................................................ 12

8. Inflorescence ramified with 1 to 2 internodes per partial inflorescence; internodes longer than bracts; flowers purple; leaves 7-15 cm long, papery with extremely elongated leaf tip, sometimes white at undersurface; capsules yellow and red with black seed and red aril; widespread .............................................................................................. M. filipes

— Inflorescence ramified or not with more than 2 internodes per partial inflorescence; internodes slightly shorter than bracts; flowers purple or white; leaves larger and stronger than in M. filipes ........................................................................................................ 9

9. Inflorescence rhachis and bracts green ...................................................................... 10

— Inflorescence rhachis and bracts purple; bracts persistent; flowers large (c. 1.8 cm), purple (tone can vary considerably between individuals from dark violet to light purple); leaves large, 20-50 cm long, 9-19 cm wide, often white below; generally in swampy areas; widespread ........................................................................................................ M. purpurea

10. Bracts deciduous; flowers small (c. 1cm), whitish; leaves max. 25 cm long and 13 cm wide, strong; fruits yellow and red; widespread .................................................. M. leucantha

— Bracts persistent; flowers large (2 cm)........................................................................ 11

11. Inflorescence erect to hanging on long petiole (8-11 cm), branched at base, up to seven bracts per partial inflorescence (> 10 cm long); bracts broad (c. 1 cm), overlapping over half of their length; flowers yellow; plant with 2 leaves only; leaf lamina up to about 45 × 20 cm; species restricted to Upper Guinea................................................ M. cuspidata

— Inflorescence hanging, slender, mostly simple, with up to 4 bracts per partial inflorescence; bracts narrow (c. 6 mm wide), non-overlapping; flowers white with yellow centre; leaf lamina up to 27 × 12 cm; so far only known for the Monts de Cristal area in Gabon........ M. alba

12. Inflorescence bracts green or red; inflorescence internodes up to 3 mm long ............ 13

— Inflorescence bracts green; inflorescence internodes ≥ 5 mm long ............................. 15

13. Inflorescence bracts green; peduncle c. 1 cm long; flowers about 2 cm long, entirely white; so far only known for the Monts de Cristal area in Gabon............... M. montsdecristalii

— Inflorescence bracts red; peduncle either absent or 1-3.5 cm long ............................. 14

14. Inflorescence on peduncle (1-3.5 cm); bracts narrow (<1 cm); flower sepals and petals purple; outer staminodes white; floral center yellow; floral tube with characteristic narrowing; widespread ...................................................................................... M. mannii

— Inflorescence sessile; bracts broad (> 1 cm); flowers white with violet center; floral tube straight; widespread .................................................................................... M. conferta

15. Inflorescence on long peduncle (5-20 cm), branching at base; partial inflorescence long (c. 10 cm) with up to 8 bracts; flower white; fruit yellow; restricted to Cameroun......... M. ramosissima

— Inflorescence on short peduncle (<5 cm), branching at base; partial inflorescence short (<10 cm) with up to 4 bracts ................................................................................... 15

16. Inflorescence peduncle 2 cm; margin of bracts glabrous; flowers large (c. 2.5 cm long) with long floral tube; sepals and petals slightly purple; floral tube white; flower with yellow center; restricted to Lower Guinea..................................................... M. cordifolia

— Inflorescence peduncle 2.5-5 cm; margin of bracts and peduncle of individual flower pubescent; restricted to Lower Guinea................................................... M. mildbraedii

Figures

FIG. 2. — Marantochloa alba A. C. Ley, sp. nov.: A, habitus with hanging, lax inflorescence (infl); B, leaf, oblong-elliptic; C, flower. A-C, A. C. Ley 242. Abbreviations: fs, fleshy staminode; o, ovary; os, outer staminode; p, petal; pa, petaloid appendage of fertile theca; s, sepal. Scale bars: A, 10 cm; B, C, 1 cm.