Nordic Journal of Botany 30: 136–143, 2012 doi: 10.1111/j.1756-1051.2012.01357.x, © 2012 The Authors. Nordic Journal of Botany © 2012 Nordic Society Oikos Subject Editor: Martin Cheek. Accepted 20 January 2012 Date of publication: 20 April 2012 Gilbertiodendron tonkolili sp. nov. (Leguminosae–Caesalpinioideae) from Sierra Leone Manuel de la Estrella, Xander M. van der Burgt, Barbara A. Mackinder, Juan A. Devesa, Matthew S. James and William D. Hawthorne M. de la Estrella (bv2esgom@uco.es) and J. A. Devesa, Depto de Botánica, Ecología y Fisiología Vegetal, Campus de Rabanales, Univ. de Córdoba, ES-14071 Córdoba, Spain. – X. M. van der Burgt and B. A. Mackinder, Herbarium, Library, Art and Archives, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK. – Matthew S. James, Biological Sciences Dept, Njala Univ., Sierra Leone. – W. D. Hawthorne, Dept of Plant Sciences, Univ. of Oxford, OX1 3RB, UK. Gilbertiodendron tonkolili Burgt & Estrella sp. nov. (Leguminosae–Caesalpinioideae) is described and illustrated. The new species is endemic to a small area in central Sierra Leone. Gilbertiodendron tonkolili is characterised by leaves bearing 4–6 pairs of leaflets; stipules comprising a lower auriculate and an upper linear part, cream-white coloured bracteoles and a pale yellow adaxial petal. The fruits have a single longitudinal vein (sometimes a second partial vein). We assess G. tonkolili here as ‘Critically Endangered’ (CR) under the 2001 criteria of IUCN. We judge it to be morphologically closest to G. bilineatum which we confirm here as ‘Vulnerable’ (VU) and for which we also provide a full description and an illustration. A table of characters useful in differentiating the two species is given and a distribution map of both species is included. In March 2006, one of the authors (Hawthorne) accompanied by A. M. B. Feika from the National Herbarium of Sierra Leone, Dr A. B. Karim and K. M. T. Kanu from the Fourah Bay College Herbarium, and others, collected a specimen (flowers and fruits) from a Gilbertiodendron tree near Bumbuna in Sierra Leone, which could not be identified. It was ascribed to a taxon with morphological affinities to G. bilineatum (Hutch. & Dalziel) J. Léonard. In March 2010, X. M. van der Burgt, accompanied by K. M. T. Kanu and J. Sesay from the Fourah Bay College Herbarium, collected two fruiting specimens, also near Bumbuna, which they independently considered might represent an undescribed taxon and which could not be identified using Hawthorne and Jongkind (2006) and Keay (1958). The genus Gilbertiodendron is currently being revised by M. de la Estrella who examined the Hawthorne and van der Burgt gatherings detailed above and confirmed that the specimens represent an undescribed species, morphologically closest to G. bilineatum. The differences between the two species are explained below in detail. Gilbertiodendron J. Léonard (Leguminosae–Caesalpinioideae) is a tropical African genus of 25–30 species, most of which are trees of primary forest (Léonard 1957, Mackinder 2005). Eleven species, including the new species presented here, occur in west Africa excluding Nigeria (Estrella et al. unpubl.). Species belonging to this genus have leaflets with marginal or submarginal glands, a 136 pair of bracteoles that enclose the flower bud, five reduced sepals, five petals of which the lateral and abaxial petal pairs are much reduced, alternate to sepals and similar to them; the well developed adaxial petal has an unguiculate base and bi-lobed apex. The androecium is usually formed from six staminodes fused at the base into a short intrastaminal tube and three stamens, although there are a few exceptions, such as G. splendidum, which have nine well developed stamens. The ovary, usually borne on a small stipe, develops into a pod with longitudinal and transverse veins, the valves twisting when mature to disperse the seeds (Polhill and Raven 1981, Hawthorne and Jongkind 2006). Descriptions follow the general format of Wieringa (1999) adapted for other Caesalpinioideae genera (Estrella et al. 2010, 2012). Gilbertiodendron tonkolili Burgt & Estrella sp. nov. Fig. (1, 2) Gilbertiodendro bilineato (Hutch. & Dalziel) J. Léonard affinis sed bracteolis cremeo-albis (nec roseo-rubris), petalo adaxiali aliquantim minore atque relative angustiore 12–13 ⫻ 14–16 mm (nec 14–16 ⫻ 18–24) et leguminis vena longitudinali singulari (nec 2–3) differt. Type: Sierra Leone, northern Region, Tonkolili District, Bumbuna. East bank of Seli (Rokel) river, just below Bumbuna waterfall, 9°03′07″N, 11°44′10″W, 15 Mar 2006 Figure 1. Gilbertiodendron tonkolili sp. nov. (a) leaf and inflorescence, (b) pair of stipules, (c) gland on leaflet margin, (d) flower, (e) bracteole outside (left) with close-up of indumentum, and inside (right), (f ) receptacle, (g) sepal, (h) lateral petal, (i) large, adaxial petal, (j) outer base of claw of adaxial petal, (k) stamen, (l) anther, (m) pistil, (n) fruit, with close-up of indumentum, (o) seed. Drawn from Hawthorne et al. 206A1 (a), (c)–(m); and from van der Burgt et al. 1457 (b), (n), (o). Drawing by Margaret Tebbs. 137 Figure 2. Gilbertiodendron tonkolili sp. nov. (a) flower, (b) fruits, (c) pair of stipules, (d) leaf, (e) stem of a tree of 77 cm dbh. Photographs by W. D. Hawthorne (a) and X. M. van der Burgt (b)–(e). (fl., fr.), W. D. Hawthorne, A. B. Karim, A. M. B. Feika, K. M. T. Kanu, M. P. Sesay, J. Sesay, J. Conteh and H. Jabie 206A1 (holotype: FHO, isotypes: FBC, K, MO, WAG). Etymology Gilbertiodendron tonkolili is named after the Tonkolili District in Sierra Leone where the type specimen was collected and from where most of the subsequent specimens were collected. The species epithet is a noun in apposition. Description Tree, to ca 30 m tall and 132 cm dbh. Twigs and branches glabrous to pubescent. Stipules in pairs, medifixed, adaxial surfaces glabrous, abaxial surfaces sparsely hairy to glabrescent, margins ciliate, upper part of stipule 20–46 ⫻ 8–14 mm, oblong-lanceolate, inrolled, persistent, fused at the base to the upper part of the other stipule for about a quarter of their length, lower part of stipule 9–40 ⫻ 138 5–15 mm, reniform, subpersistent. Leaves alternate, 4–6jugate, 18–43 ⫻ 13–28 cm, largest pair of leaflets is the upper or penultimate pair; petiole 4–11 mm long, 2.5– 5.0 mm diameter, more or less terete, pubescent to glabrescent; rachis 8–29 cm long, rounded abaxially, canaliculate and slightly articulated at the insertion of each pair of leaflets adaxially, hirsute to glabrescent; stipels absent; petiolules 3–6 mm long; leaflets opposite, coriaceous, 9–14 pairs of lateral veins, brochidodromous, midrib sparsely hairy to glabrescent on both sides of leaflet, leaflet blade glabrous on both sides, although some hairs appear on the basal part as an extension of the indumentum of the petiolules; 0–4 glands along each margin of the leaflet, generally two glands located on the distal margin near the base, an emarginate gland at the proximal margin close to the apex, and a gland at the top of the midrib; midrib prominent on both sides, terete; base of the leaflet asymmetric, proximal half wider than distal half, proximal margin inserted at 0–3 mm below the distal margin insertion; basal leaflet 6–14 ⫻ 2.5–6.0 cm, oblong-obovate, with acuminate or emarginate apex; largest leaflet 10–30 ⫻ 3–8 cm, oblong-lanceolate, with acuminate apex, acumen up to 5 mm long. Inflorescence a compound panicle, (3–) 15–43 cm long, lax, axillary, sometimes branched at base; rachis densely covered with hairs ca 0.1 mm long, with sparse hairs up to 0.5 mm long intermixed, ca 4 lateral branches, up to 15 cm long and up to 35-flowered. Bracts ca 4.5 ⫻ 2.6 mm, caducous, deltoid, slightly apiculate, cupuliform, densely hairy on outer surface, inner surface covered with a few scattered hairs, more densely hairy towards margins; pedicel 9–14 mm long, ca 1 mm in diameter, with 4 ridges, densely covered with short and longer hairs; bracteoles cream-white, ca 9–11 ⫻ 5–7 mm, oblong, cupuliform, concave and slightly beaked in outline, outside densely tomentose with short and longer hairs, inside glabrous to sparsely tomentose near margin, edge glabrous, with a beak ca 1.7 mm long culminating in a gland at apex. Receptacle ca 1.5 ⫻ 2.0 mm, hairy in the middle, upper and lower parts glabrous. Sepals 5, white, 4.0–6.5 ⫻ 1–2 mm, narrowly triangular, broadest at base, apex obtuse to acuminate, glabrous, abaxial sepal often hairy at margins near the base, adaxial sepals united for 0.2 mm covering part of the adaxial petal claw; the other 3 sepals free. Petals 5, alternate to sepals; adaxial petal large, light yellow, deeply bi-lobed, 12–13 ⫻ 14–16 mm, including claw 4–5 ⫻ 2 mm, densely hairy on lowest 1.0–1.5 mm of claw outside, upper part of claw and petal lobes glabrous; lateral and abaxial petal pairs white, equal in size to sepals, 4.0–6.5 ⫻ 1–2 mm, oblong, apex obtuse to acuminate, broadest at base, glabrous. Fertile stamens 3, alternate with abaxial petals, filaments 18–20 mm long, mainly white, upper part pink–purple, lower third hairy; anthers orange– brown, 5.0 ⫻ 2.7 mm, slightly hairy on external face; staminodes 6, filiform, fused into a short intrastaminal tube, ca 1 mm long, glabrous. Ovary ca 5 ⫻ 3 mm, oblong-rhombic in shape, densely hispid, covered with dark brown hairs, stipe 1 mm long, hairy; style ca 27 mm long, white except for the upper part pink–purple, lower third hairy; stigma ca 0.8 mm in diameter, capitate. Pod grey–brown to ferruginous, 17–30 ⫻ 5.0–8.5 cm, oblong-rectangular, 2–7-seeded, broadly beaked, sparsely to densely covered with hairs, one valve of a single pod sometimes much more densely ferruginous in colour than the other valve, with a single longitudinal vein, 14–25 mm from the upper suture, sometimes with a second partial longitudinal vein, running along 1/3 to 2/3 of the length of the pod, at 1–5 mm from the upper suture. Seeds oblong to irregular in shape, brown, up to 5.0 ⫻ 3.5 ⫻ 1.0 cm when fresh. Seedlings: hypocotyl 4–6 cm; cotyledons fallen, not seen; epicotyl 14–17 cm; 2 opposite leaves; always 2 pairs of leaflets per leaf, the terminal pair slightly larger; petiole 10–22 mm long; rachis 20–32 mm long; smallest leaflet 8.5–10.5 ⫻ 2.4–3.8 cm; largest leaflet 11–4 ⫻ 3.0–4.3 cm. Phenology Flowering and fruiting specimens have been collected in March. The individual tree from which the type collection was gathered was still flowering and fruiting in April (collector’s notes, Hawthorne 206A1). Figure 3. Distribution of Gilbertiodendron tonkolili sp. nov. (circles) and G. bilineatum (triangles). Collections that could not be identified to either species with certainty are represented by crosses. 139 Distribution and habitat Gilbertiodendron tonkolili is endemic to Sierra Leone. The species is found on well-drained sandy and/or rocky soils; banks of rivers and remnant forest patches; 100–180 m a.s.l. (Fig. 3). Conservation status Gilbertiodendron tonkolili only occurs in a triangular area of ca 12 ⫻ 10 km in central Sierra Leone (Fig. 3). The extent of occurrence is less than 100 km2. The number of sites is more than one but the species is severely fragmented and the sites are all under the same threat of deforestation, which means that there is effectively one single location, according to the definition in IUCN (2001). The area where the species is found is outside the known occurrence of iron ore deposits in the Sula Mountains; therefore the new species is not directly threatened by the proposed mining of these deposits. The Bumbuna hydroelectric dam, constructed in the Rokel River upstream of Bumbuna after the type collection was made in 2006, may have destroyed some stands of G. tonkolili. However, the type locality is situated just below the dam. The new species has been recorded in a number of sites along the Rokel River and its tributaries, which often have an up to ca 20 m wide strip of trees on their banks. These strips of forest partly consist of gallery forest and partly are remnants of a once more continuous forest. They have not been converted to farmland because of the often steep and rocky banks and variable water level of the river. The species grows gregariously; a strip of forest of 100 m long may contain more than 10 mature trees. G. tonkolili has also been recorded in so-called ‘society bushes’, isolated small patches of forest which were not converted to farmland for local cultural reasons. It is likely, however, that the species was much more abundant before farmers settled in the area. The decline in numbers of mature trees over the last 3 generations is likely to have been more than 80%, as observed by the collectors. The collectors have also observed that some trees were recently damaged or logged to make room for the construction of bridges. The deforestation is expected to continue, partly due to the local demand for construction wood. All sites where the species has been found currently lie outside protected areas. Gilbertiodendron tonkolili is assessed here as ‘Critically Endangered’ (CR) A2acd ⫹ 3cd; B1ab (iii, v) under the criteria of IUCN (2001). Additional specimens examined (paratypes) Sierra Leone. Tonkolili district, south of Bumbuna, Rokel River near villages Kapeteh and Kabumba (9°0′36″N, 11°49′44″W), 1 Mar 2010 (fr.), X. M. van der Burgt 1423 (BR, FBC, G, K, MO, P, SL, WAG), same loc. (9°0′45″N, 11°49′48″W), 9 Mar 2010 (fr.), X. M. van der Burgt 1457 (BR, FBC, G, K, MO, P, SL, WAG), same tree, 11 Dec 2010 (seedlings), X. M. van der Burgt 1498 (BR, FBC, FHO, K, MO, P, SL, WAG); Bombali District, Rokel River, western bank (9°0′18″N, 11°50′6″W), 3 Mar 2010 (fr.), A. M. B. Feika 98 (FBC, K, SL); Rokel River, ca 1.5 km southeast of Kamonkow village (8°59′51″N, 11°50′36″W), 11 Mar 2010 (sterile), Pollard 1420 (FBC, K, SL, WAG), Rokel 140 River (9°1′3″N, 11°49′55″W), 11 Mar 2010 (fr.), Pollard 1429 (FBC, K, SL). Gilbertiodendron bilineatum (Hutch. & Dalziel) J. Léonard (1954, p. 58) (Fig. 4) Basionym: Macrolobium bilineatum Hutch. & Dalziel (1928a, p. 347) Type: Sierra Leone, near Kahreni (Limba), 7°38′N, 11°47′W, 9 Apr 1892, G. F. Scott-Elliot 5588 (lectotype designated by Léonard 1957, p. 236, K, isolectotype: BR). Tree, to ca 30 m tall and 150 cm dbh. Twigs and branches glabrous to densely pubescent. Stipules in pairs, medifixed, adaxial surfaces glabrous, abaxial surfaces mostly glabrous but glabrescent to hairy near the point of insertion, upper part of stipule, (28–)35–65 ⫻ 11–18 mm, oblong-lanceolate, persistent, not inrolled, fused at the base to the upper part of the other stipule for about a quarter of their length, lower part of stipule 8–36 ⫻ 4.5–21 mm, reniform, subpersistent. Leaves (17–) 34–38 (–60) ⫻ (11–) 16–30 cm, alternate, 4–8-jugate, largest pair of leaflets is the terminal, penultimate or third pair; petiole (4–) 7–14 mm long, 3–6 mm diameter, ⫾ terete, densely hairy to glabrescent; rachis (7.5–) 20–28 (–42) cm long, rounded abaxially, canaliculate and slightly articulated at the insertion of each pair of leaflets adaxially, puberulous to glabrescent; stipels absent; petiolules 2.8–5.0 mm long; leaflets opposite, coriaceous, minutely mucronate, with 10–15 pairs of lateral veins, brochidodromous, glabrous; 0–3 glands on each margin of the leaflet, generally one or two glands located on the distal margin near the base, and an emarginate gland located on the proximal margin, near the apex; midrib prominent on both leaflet surfaces, terete, base asymmetric; proximal half of the leaflet lamina wider at base than distal half, proximal margin inserted at 0–3 mm below the distal margin insertion; basal leaflet 6.0–12.5 ⫻ 2–6 cm, oblong, apex acuminate; largest leaflet 10–23 ⫻ 3–7 cm, oblong-lanceolate to obovate-lanceolate, apex acuminate, acumen 5–12 mm long. Inflorescence a compound panicle, (8.5–) 13.5–19.0 (–25.0) cm long, axillary or terminal, rachis densely covered with matted hairs, sometimes branched at base, with up to 6 lateral branches, each 5.5–11.0 cm long and 12–38-flowered. Bracts 4–5 ⫻ 3–4 mm, caducous, deltoid, slightly apiculate, cupuliform, densely hairy with matted hairs on outer surface, covered with hairs at margins, inner surface more or less glabrous; pedicel 8.0–24.5 mm long, ca 1 mm diameter, slightly quadrangular to circular in cross section, densely covered with two types of hairs; bracteoles pinkish–red, 8.0– 13.5 ⫻ 6–9 mm, oblong, cupuliform, concave and slightly beaked in outline, outside densely tomentose, covered with short hairs with sparse longer hairs intermixed, inside tomentose, more densely hairy towards margins, edge glabrous, with a 1.0–2.1 mm long beak culminated in a gland at apex. Receptacle 2.2–2.5 ⫻ 2.5–3.6 mm, glabrous to partly hairy. Sepals 5, white, 3.0–4.3 ⫻ 1.2–2.0 mm, narrowly triangular, obtuse to acuminate at apex, glabrous, two adaxial sepals united for 0.3–2.0 mm and covering part of Figure 4. Gilbertiodendron bilineatum. (a) leaf and inflorescence, (b) gland on leaflet margin, (c) pair of stipules, (d) flower, (e) adaxial petal, (f ) intrastaminal tube with staminodes and base of stamens, exposed by removal of ovary and posterior petals, (g) anther, (h) fruits. Drawn from King 295 (a), (b), (d)–(g), Chevalier 22662 (c) and from Small 709 (h). Drawing by Margaret Stones. Reproduced from Keay (1958). the adaxial petal claw; remaining 3 sepals free. Petals 5, alternate to sepals; adaxial petal large, yellow, deeply bi-lobed, 14–16 ⫻ 18–24 mm, including claw 5.0–7.5 ⫻ 1.2–1.8 mm, mostly glabrous, but moderately hairy at the top of the claw outer surface; lateral and abaxial petal pairs white, equal in size, 3.2–4.5 ⫻ 1.1–1.7 mm, oblong, apex acuminate, glabrous. Fertile stamens 3, alternate with abaxial petals, filaments 13–15 mm long, their lower third 141 hairy; anthers 3.5–5.0 ⫻ 2–3 mm, densely hairy on external face; staminodes 6, filiform, fused into a short intrastaminal tube, 0.5–1.4 mm long, glabrous. Ovary 5.5–6.2 mm long, oblong-rhombic in shape, densely hispid, covered with brown hairs; style ca 18 mm long, lower part hairy; stigma 1 mm in diameter, capitate. Pod 14–30 ⫻ 3.5–9.0 cm, oblong rectangular, 3–4-seeded, beaked, glabrescent, patches of hairs remaining, 2 to 3 longitudinal veins located at ca 5–10, 15–25 and 30–40 mm from the upper suture. Seeds and seedlings unknown. Phenology Flowering is recorded from November to April; fruiting from November to May. Distribution and habitat Gilbertiodendron bilineatum is found in Sierra Leone, Liberia, Ivory Coast, Ghana and possibly also in Guinea; on river banks and in swampy areas; 40–400 m a.s.l. (Fig. 3). Conservation status Gilbertiodendron bilineatum was assessed as ‘Vulnerable’ (VU) A1c, B1 ⫹ 2c by Hawthorne (1998), because the species is very rare and has disappeared from previously recorded localities and because habitat losses have been caused by mining, logging and commercial forestry activities (IUCN 2011). The species is known from Sierra Leone, Liberia, Ivory Coast and Ghana (Poorter et al. 2004), and maybe from Guinea (below). It occurs over too large an area (extent of occurrence) to be considered ‘Vulnerable’ under IUCN criterion B1; but would qualify under criterion B2 if grid cells of 4 km2 are used and if the number of currently existing localities is 10 or less. However, Poorter et al. (2004) present a distribution map with 15 localities. Although most of these were collected over 50 years ago, the number of sites could still be over 10. Of the forest that covered west Africa at the beginning of the 20th century, 20–50% remains (Poorter et al. 2004). The species must have undergone a considerable reduction in population during the last 3 generations, considering that the species is a large forest tree, adult trees presumably have a high average age and in this species 3 generations therefore represent a long period of time. The population reduction is expected to continue in the future, because most of the historic localities of the species are outside protected areas. Based upon current knowledge, the IUCN conservation status is here reassessed as ‘Vulnerable’ (VU) A2cd ⫹ 3cd (IUCN 2001). Vernacular names Sierra Leone: gogo (Mende); kpendi-guli (Mende). Ivory Coast: medjilagba (Abe). Ghana: kotoprepre (Akan-Wasa). These names are also used for a few other species of Caesalpinioideae (Burkill 1995). Additional specimens examined Ghana. Ashanti, Obuasi, Numia Forest Reserve, Asamang, (5°54′N, 1°30′W), 8 Nov 1956 (fr.), A. A. Enti 6495 (K). Ivory Coast. Attié, environs de Yacassé, 27 Dec 1909 (fr.), A. Chevalier 22662 (K, WAG); Enchi (5°49′N, 2°49′W), (fl.), Vigne F. H. 3156 (WAG). Liberia. Sapo N. P., along Sinoe River (5°20′N, 8°48′W), 25 Nov 2002 (fl.), C. C. H. Jongkind, F. Blyden et al. 5437 (WAG). Sierra Leone. Falaba (9°51′N, 11°19′W), 20 Mar 1916 (fl.), K. Burbidge 475 (K); Kenema Div., Joru Town, Gaura Chiefdom (7°41′N, 11°03′W), 10 Nov 1950 (fl.), H. C. King 295 (K), 3 Jan 1951 (fr.), H. C. King 308 (K); Gola forest, 21 May 1952 (fr.), D. Small 703 (K), 20 May 1952 (fr.), D. Small 709 (K). Currently unplaced specimens The two species cannot be separated vegetatively. Consequently, sterile and partial collections cannot be assigned confidently to one or other of the two species. Gilbertiodendron bilineatum occurs with certainty in four countries (Ghana, Ivory Coast, Liberia and Sierra Leone), whilst G. tonkolili is known from a small area in Sierra Leone only. As G. bilineatum is much more widespread than G. tonkolili, it is likely that most of the sterile collections cited here are G. bilineatum. These collections are included on the map with cross symbols in order to complement the overall distribution of the two related taxa. Guinea. Woundire, 43 km southsouthwest of Sangaredi (10°42′26″N, 13°50′38″W), 12 Feb 2011, A. Gandeka 169 (K), Telissita, 52 km southsouthwest of Sangaredi (10°38′58″N, 13°53′48″W), 17 Feb 2011, A. Gandeka 195 (K). Ivory Coast. Forêt à 13 km de Sakré, 23 Feb 1973, Aké Assi 11956 (K). Liberia. Between Sellakuri and Yanga, 5 Mar 1892, G. F. Scott-Elliot 5070 (K). Sierra Leone. Kenema Div., Joru Town, Gaura Chiefdom, 7°41′N, 11°03′W, H. C. King 143 (K). Table 1. Diagnostic characters between Gilbertiodendron tonkolili sp. nov. and G. bilineatum. Key characters are in bold. Character G. tonkolili G. bilineatum Bracteole colour Sepal length (mm) Adaxial petal (mm) Claw length (mm) Adaxial petal indumentum cream-white 4.0–6.5 12–13 ⴛ 14–16 4–5 mostly glabrous, densely hairy on lowest 1.0–1.5 mm of the claw outside 18–20 slightly hairy abaxially 1.0(ⴚ1.5) sparsely to densely covered with hairs pinkish red 3.0–4.3 14–16 ⴛ 18–24 5.0–7.5 mostly glabrous, moderately hairy at the top of the claw outside 13–15 densely hairy abaxially 2ⴚ3 glabrescent, patches of hairs remaining Stamen filament length (mm) Anther indumentum Pod longitudinal veins Pod indumentum 142 Nomenclatural notes on G. bilineatum Hutchinson and Dalziel (1928a, 1928b) published Macrolobium bilineatum in two works, first in the ‘Flora of west tropical Africa’ which appeared in July 1928 and then in the ‘Bulletin of miscellaneous information, Kew’ which appeared in December 1928. Therefore, the first and thus correct place of publication for M. bilineatum is Hutchinson and Dalziel (1928a). No type was cited in Hutchinson and Dalziel (1928a), but in Hutchinson and Dalziel (1928b, p. 399) they cited: “Sierra Leone: Kahreni, Apr., Scott-Elliot 5588 (type)”. Because the authors did not indicate in which herbarium it was deposited, no holotype was designated. Léonard (1957, p. 236) noted that the type material of G. bilineatum was “Scott-Elliot 5588 (K!)” and in so doing he effectively selected this as a lectotype. Differences between G. tonkolili and G. bilineatum Gilbertiodendron tonkolili is a species closely related to G. bilineatum; the two species share the same gland pattern on the leaflets and the same general aspect in inflorescence type. The two species cannot be easily separated vegetatively, although G. tonkolili has 4–6 pairs of leaflets, while G. bilineatum has 4–8 pairs. However, both species can be distinguished based on characters of the flower and the fruit (Table 1). Bracteoles of G. tonkolili are white-cream in contrast to the pinkish red bracteoles of G. bilineatum (collection notes of Jongkind 5437; Poorter et al. 2004, p. 231). The adaxial petal of G. tonkolili is mostly glabrous, but is densely hairy on the outer surface of the lowest 1.0–1.5 mm of the claw; while G. bilineatum presents an adaxial petal which is also mostly glabrous but hairy on the outer surface of the top of the claw. Finally, pods of G. tonkolili present a single longitudinal vein close to the upper suture of each valve (very rarely 1 vein running the full length of the pod and a second shorter vein extending one to two thirds the pod length) whereas pods of G. bilineatum present 2 to 3 longitudinal veins. Acknowledgements – The new species Gilbertiodendron tonkolili was discovered during a vegetation survey for the Bumbuna Hydroelectric Project, prior to the building of the dam in the Rokel river. The new species was found again during a vegetation survey hosted and funded by African Minerals Limited, Freetown. Andy Huckbody, head of the environment team of African Minerals, is thanked for supporting botanical research. Permission to do botanical research in Sierra Leone was given by Mrs Kate M. B. Garnett, assistant director of the forestry division at the Ministry of Agriculture, Forestry and Food Security. The fieldwork was assisted by Abdulai Feika of the National Herbarium of Sierra Leone at the Njala Univ. (head, Dr A. J. Sundufu) and by Kabbie M. T. Kanu and Julius Sesay of the Fourah Bay College Herbarium (head, Dr Abdul B. Karim). The authors wish to thank the staff of the cited herbaria for their support during our visits and/or for the loan of material. This work was partially financed by the Spanish Science and Innovation Ministry (CGL2008-02982-C03-03/CLI and CGL2009-07405/BOS). Manuel de la Estrella was funded by the Spanish Juan de la Cierva grant JCI-2009-05243 and also by the Spanish Science and Innovation Ministry and visited K herbarium thanks to a BenthamMoxon Trust grant. We thank Martin Cheek for his comments on a previous draft of the manuscript and Gwilym P. Lewis for his valuable review of our manuscript, Margaret Tebbs for the illustration and Melanie Thomas for translating the diagnosis into Latin. References Burkill, H. M. 1995. The useful plants of west Tropical Africa. Vol. 3, families J–L. – R. Bot. Gard. Kew, p. 121. Estrella, M. et al. 2010. Taxonomic revision of Daniellia (Leguminosae: Caesalpinioideae). – Syst. Bot. 35: 296–324. Estrella, M. et al. 2012. A morphological re-evaluation of the taxonomic status of the genus Pellegriniodendron (Harms) J. Léonard (Leguminosae–Caesalpinioideae–Detarieae) and its inclusion in Gilbertiodendron J. Léonard. – South Afr. J. Bot. 78: 257–265. Hawthorne, W. 1998. 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