Laccosperma cristalensis Couvreur & Niangadouma, 2016

Couvreur, Thomas L. P. & Niangadouma, Raoul, 2016, New species of Uvariopsis (Annonaceae) and Laccosperma (Arecaceae / Palmae) from Monts de Cristal, Gabon, PhytoKeys 68, pp. 1-8 : 4-7

Laccosperma cristalensis Couvreur & Niangadouma sp. nov. Figure 3

Type.

GABON, Estuaire: Monts de Cristal National Park, Mbé sector, forest around the antenna in Tchimbélé, ca. 40 km from Kinguélé, 0°36'21.240"N; 10°24'42.480"E, 13 Jun 2016, T.L.P. Couvreur 1142 (holotype: WAG!; isotypes: LBV!, P!, G!, K!) .

Diagnosis.

Resembles Laccosperma korupensis Sunderland by the lack of acanthophylls on the cirrus. Differs from Laccosperma korupensis by the fewer pinnae (5-8 vs 10-18) sigmoid in shape (vs lanceolate) lacking spines along the margin (vs with spines) and the short 3-5 mm truncated ocrea (vs 8 cm long and tapering to a point).

Description.

Clustered, slender palm climbing to 15 m. Stem, circular to oval in cross section, 5-8 mm in diameter; internodes 10-20 cm long. Leaf sheath finely striate, sparsely to moderately armed with fine, green, black tipped, downward and upward pointing spines; sheaths near leaf junction occasionally unarmed; ocrea 3-5 mm long, truncate, round, green, armed with very fine black-tipped spines. Leaves up to 80 cm long; petiole to 3-4 cm long × 4 mm wide, abaxially rounded, adaxially grooved, armed abaxially with short 2-4 mm long, inequidistant, reflexed black spines; rachis to 30 cm long, angular in cross section, armed as the petiole; cirrus to 45 cm long armed as the rachis, although spines become smaller distally; pinnae, 5-8 on each side of the rachis, inequidistant, usually sub-equidistant proximally and borne in pairs distally, sigmoid, finely acuminate at apex, bluntly cuneate at base, 15-16 cm long, 3-4 cm broad at widest point, prominent transverse veinlets, margins lacking spines; acanthophylls absent. Flowers and fruits unknown.

Distribution.

Only known to date from Gabon, from one locality in the Monts de Cristal National Park, Mbé sector, Tchimbélé.

Habitat.

This species was found growing in an old secondary forest, on a slope.

Preliminary conservation status.

Data deficient. DD. Laccosperma cristalensis is only known by a single collection, thus it is hard to provide an accurate status here. By providing a name to this species, we hope that others will be able to identify potential past collections. The type locality is located in an old secondary forest within the National Park Monts de Cristal, Mbé sector, near Tchimbélé. This forest is, however, close to the telephone antenna area which is regularly maintained by cutting. Important hunting activity was also seen there, suggesting important human activity.

Etymology.

Named after the Monts de Cristal National Park in northwestern Gabon, home to an important number of plant species and endemics.

Discussion.

Laccosperma cristalensis closely resembles Laccosperma korupensis by the absence (or near absence) of acanthophylls on the cirrus (extension of the leaf rachis). These are the only two species of African rattans (subtribe Ancistrophyllinae ) to share this character. However, Laccosperma cristalensis is easily distinguished from Laccosperma korupensis by having fewer pinnae (5-8 versus 10-18) which are sigmoid versus lanceolate, lacking spines along the margin versus presence of spines along the margin and an ocrea that is 3-5 mm long and truncated versus 7-10 cm long and tapering to a point ( Sunderland 2012). To date none of these species have been collected flowering or fruiting, however, the vegetative characters alone suffice to clearly distinguish them. The total number of species in Laccosperma is now 7, although new species are yet to be described from West Africa ( Faye et al. 2016).

Figures

Figure 3. Laccosperma cristalensis. A Leaf, notice lack of acanthophylls on cirrus B Detail of leaf sheath and ocrea C Detail of sigmoid pinnae. (Couvreur 1142). Photos Thomas L. P. Couvreur.