Eriosema arenicola (Verdc.) Maesen & Wieringa, 2012

Eriosema arenicola (Verdc.) Maesen & Wieringa View in CoL , stat. nov. — Map 1

Basionym: Eriosema laurentii De Wild. subsp. arenicola Verdc., Kew Bull. View in CoL 25 (1971) 114. — Type: Deighton 2679 (holo K; iso P n.v.), Sierra Leone, behind H.W.M. between Kent and Tombo, on sandy shore. – Paratypes: Deighton 2277 (K), Sierra Leone, Turtle Islands, Yele; Dinklage 3279 (A, BM, K, P, US), Liberia, near Monrovia, Kings Farm. Additional material: Adam 27917 (P n.v., WAG), Guinea, Kindia; Adam 28403 (P), Liberia, Buchanan; Kunkel 6 (WAG), Liberia,Upper Mesurado River,near Monrovia.

Perennial herb with long vertical tap root, procumbent or not, with ascendant or erect branches up to 30–40 cm long, appressed-pubescent; trifoliolate leaves, leaflets rather co- riaceous, narrow-lanceolate, 2 –9 by 0.3–1 cm, apex acute, mucronate, short-pubescent above and below, veins below prominent, brown, not opposite, pedicels 1–2 mm long. Stipules lanceolate, c. 8 mm long, striate, almost glabrous, margins pu- bescent. Inflorescences pedunculate pseudoracemes, 0.3–4 cm long, flowers c. 3–12, papilionaceous, c. 5 mm long, corolla

1 Netherlands Centre for Biodiversity Naturalis (section NHN), Herbarium Vadense (WAG), Biosystematics Group, Wageningen University, Gen. Foulkesweg 37, 6703 BL Wageningen, The Netherlands;

corresponding author e-mail: jos.vandermaesen@wur.nl.

yellow or red. Pods black, brown to grey-hairy, rounded-oblong, c. 1 cm long, 1–2 seeds.

Ecological note — The plants look capable of surviving savannah fires. Except for Adam 27917 all localities are coastal sites.

Conservation assessment — Based on an area of extent of nearly 48 000 km 2 and on an area of occupancy of c. 15 000 km 2 when using grid cells of 56 km, E. arenicola would be classified as Least Concern. However, since the most recent collection ( Adam 28403) is already 38 years old, at least the Monrovia locality of the species is probably lost, and the actual distribution area along the coast is confined to a very narrow savannah strip that is not considered by both the AOO and EOO calculations, we consider E. arenicola is under quite some threat at present and we assess it as Threatened.

Notes — This taxon belongs to the group around E. glomeratum (Guill. & Perr.) Hook.f. , of which species Verdcourt (1971) indicated the lectotype: Perrottet s.n. (P, barcode P00373661), Senegal, Kounoun, 12 mars 1829. It is a smallish specimen with sessile capitate inflorescences, in West Africa difficult to separate from var. elongatum (Baill.) Baker , with pedunculate inflorescences; hence both Verdcourt and Jacques-Félix (1971) synonymised the latter with var. glomeratum . However, in Flore du Congo-Belge et du Ruanda-Urundi Hauman (1954) kept var. elongatum apart, and the specimens are reasonably easy to sort in the more central part of Africa. In Flora Zambesiaca both these taxa are absent, apart from a mention as doubtful ( Verdcourt 2001). Hepper in Flora of West Tropical Africa (1958) quoted Deighton 2679 and Dinklage 3279 under E. glomeratum as undescribed sea coast forms.

In the Flore Analytique du Bénin ( Akoègninou et al. 2006) and the Checklist of Gabon ( Sosef et al. 2006) E. laurentii was considered a variety of E. glomeratum , but upon further consideration it is distinct enough to merit the rank of species, just as Hauman (1954) and Jacques-Félix (1971) preferred. As is apparent from Map 2 View Map 2 and 3 View Map 3 these two species have a different distribution and hence ecology. Eriosema laurentii occupies a habitat that, albeit savannah, is closer linked to the forested areas than E. glomeratum , the latter avoids the dense forest region as a whole.

The following key may facilitate to separate the species and varieties: 1. Leaflets linear to narrowly lanceolate, 2–9 by 0.3–1 cm, leaflets 4.5–15.5 times as long as wide, apex acute, mucronate, short-pubescent above and below, indumentum on the ribbed branches appressed.............. E. arenicola View in CoL

1. Leaflets (narrowly) elliptic or oblanceolate, 1.5–12 by 0.6–2.5 cm, leaflets 1.6–8.7 times as long as wide, apex rounded or attenuate, indumentum appressed or upright......... 2

2. Indumentum on branchlets appressed, hairs c. 1 mm long, rarely a few hairs of c. 2 mm occur, hairs usually concen- trated on the ribs creating a stripe pattern. Leaflets (narrowly) elliptic, 3–12 by 0.6–2 cm, leaflets 2.8–8.7 times as long as wide, apex and base attenuate, venation pinnate......................................... E. laurentii View in CoL

2. Branches with long (> 2 mm) upright hairs, often also smaller hairs present, hairs do not create a stripe pattern. Leaflets oblanceolate, 1.5–7.5 by 0.5–2.5 cm, leaflets 1.5–6 times as long as wide, apex rounded or cuneate, venation with the basal secondary veins reaching or surpassing the middle of the leaflet........................ E. glomeratum View in CoL 3

3. Inflorescences sessile, (6–)9–16 flowers or more...................................... var. glomeratum View in CoL

3. Inflorescence pedunculate, (2–)3–9(–10) flowers........................................ var. elongatum View in CoL