Inversodicraea liberia Cheek, 2017

Tchouto, P. & Burgt, X. van der, 2017, A synoptic revision of Inversodicraea (Podostemaceae), Blumea 62 (2), pp. 125-156 : 153-154

30. Inversodicraea liberia Cheek , sp. nov. — Fig. 8

Differs from Inversodicraea pepehabai in the scale-leaves being arranged in c. 3 ranks (not 5), the basal half of the scale-leaves being appressed and sheathing the stem (not patent, with the leaflet flat), the fruit 1–1.2 mm long (not 3–4 mm long). — Type: Robert M. Warner 87A (holotype K), Liberia, on rocks in water, 1942–43.

Etymology. Named (noun in apposition) for the country of Liberia.

Probably annual rheophytic herb, root not recorded, 1.5 cm tall. Stems erect, 2–4-branched, terete, 0.5 mm diam at base, main stem 40–50 % covered by scale-leaves arranged in c. 3 ranks, stem apex more densely covered ( Fig. 8 ). Scale­leaves 0.75(–1.5) by (0.25–) 0.4–0.6 mm with proximal half appressed and sheathing the stem, the lateral margins folded towards the stem; distal portion dilating, the apex broadly rounded, sometimes with a lateral triangular lobe c. 0.1 by 0.1 mm. Leaves c. 4 mm long, lateral insertion, once dichotomous, petiole 3 mm long, dorsiventrally flattened, 0.2–0.3 mm wide at base, blade ribbon-like, c. 0.1 mm wide, 0.6 mm long, apices rounded. Spathellum in bud, unrecorded, at dehiscence subglobose, 0.75 by 0.6 mm. Pedicel 2.5–3(–3.7) mm long. Tepals and androecium unrecorded. Gynophore 0.25 mm long. Ovary and styles unrecorded. Fruit ellipsoid, brown, 1–1.1 by 0.5–0.6 mm, apex rounded, base gradually decurrent into gynophore, decorticating to expose 6 vascular strands; longitudinal ribs 6, equal, the commissural ribs only weakly developed with a central longitudinal groove (suture); dehiscing into two equal non-caducous valves, dehiscence extending into gynophore. Seeds 1.1 by 0.75 mm.

Distribution — Only known from the type specimen in Liberia.

Habitat & Ecology — Unknown, but probably waterfalls in the lowland rainforest zone.

Conservation — Since the location for I. liberia , and therefore threats, are unknown, we assess the species here as NT, indicating that since it is known from a single location, probably with only a few hundred plants, it is vulnerable to loss from hydroelectric projects and other habitat modification events such as silt input into rivers from run-off due to logging and/or from artisanal mining.

Notes — Warner 87 (K) is a mixture of two species, determined by Cusset in 1974 as Macropodiella garrettii (C.H.Wright) C.Cusset (here designated as Warner 87) and Ledermanniella cf. gabonensis C.Cusset (here designated as Warner 87A). It is 87A, L. cf. gabonensis , that is here described as I. liberia . Inversodicraea gabonensis and I. liberia are two geographically distant yet both share a similar habit, and membranous pepehabai .

scale-leaves. However, I. gabonensis has scale-leaves tapering at the apex and which are appressed to the stem, covering it completely in the distal half, while in I. liberia the scale-leaves cover only 40–50 % of the stem and the distal part of the scale-leaves are often spreading,> 50 % having a broadly rounded apex. Moreover, in I. liberia the fruits are only c. 1 mm long vs c. 2 mm in I. gabonensis .

Inversodicraea liberia is possibly more closely related to I. pepehabai of neighbouring Guinea than to I. gabonensis since they are geographically close. Both species share more or less spreading or patent scale-leaves, which occurs nowhere else in those Inversodicraea species with membranous scale-leaves which lack regular margin ornamentation or lobes. The two species can be distinguished using the characters shown in Table 4. Although Warner 87 was seen by Cusset in 1974, she did not refer to it in her revision of Ledermanniella subg. Phyllosoma ( Cusset 1983) .

Warner 87 (with 87A), comprising the two species of Podostemaceae referred to, appears to be the first and so far only record of any member of that family from Liberia (apart from Tristicha trifaria , mentioned in Taylor 1954). Undoubtedly many more species of Podostemaceae , including those new to science, await discovery in Liberia since neighbouring countries east and west each have several endemic species of the family. The absence of any previous published record to Warner 87 is probably partly due to the incomplete nature of both species that it contains. Regarding I. liberia , the material is both meagre, and lacks flowers. The localisation is also poor since only ‘Liberia’ is given as the source. Better and more complete material which would allow a full description of the species, would be welcomed. The species was described to encourage interest in this distinct species and to guard against the possibility that it might not be found again.

Figures

Fig. 8 Inversodicraea liberia Cheek. a. Habit, fruiting plant;b. detail of stem below spathellum, * indicates young scale-leaves;c. post-anthetic flower showing remains of 2 anthers and spathellum; d. fruit, dehiscence incipient, note absence of commissural ribs; e. dehiscing fruit with seeds; f. transverse section of fruit; g. seed (all from R.M. Warner 87A, K). — Scale bars: a = 2 mm; b–g = 1 mm. — Drawn by Andrew Brown.