Gilbertiodendron bambolense Burgt

van der Burgt, X.M., Mackinder, B.A., Wieringa, J.J. et al. The Gilbertiodendron ogoouense species complex (Leguminosae: Caesalpinioideae), Central Africa. Kew Bulletin 70: 29. DOI https://doi.org/10.1007/s12225-015-9579-4

Type

Type: Zaire [Congo (Kinshasa)], Yahila (Bambole), rive gauche en face de Yangambi, le long de la rivière Loowe, 11 Sept. 1938, J. Louis 11234 (holotype K! [K000745742], isotypes BR!, WAG!).

Morphology General Habit

Tree, to c. 40 m tall

Morphology Trunk

Trunk straight, cylindrical, to 120 cm diam. Twigs glabrescent or glabrous

Morphology Leaves Stipules

Stipules in pairs, free; reniform part persistent, flat, 10 – 22 × 6 – 15 mm, glabrescent or glabrous; lanceolate part of stipule not seen

Morphology Leaves

Leaves paripinnate, to 32 × 20 cm; petiole 3 – 8 mm long, 1.5 – 4 mm diam., sparsely puberulent with hairs to 0.4 mm long, or glabrous; leaf rachis 7 – 27 cm long, glabrous, rachis of juvenile leaves sparsely puberulent, hairs to 0.3 mm long, stipels absent; petiolules 2 – 4 mm long, sparsely puberulent to glabrous, with hairs to 0.3 mm long

Morphology Leaves Leaflets

Leaflets papery, opposite, 4 – 7 pairs, narrowly elliptic to elliptic, 5 – 13 (– 20) × 1.5 – 5 (– 6) cm; smooth, somewhat glossy and glabrous both sides, lower surface same colour or somewhat lighter, midrib glabrous above, glabrescent to glabrous and prominent below; 7 – 10 pairs of secondary veins; leaflet base cuneate to obtuse, slightly oblique; apex acuminate and mucronate, acumen 0.3 – 1.5 cm long

Morphology General Glands

Glands 0 – 1 (– 2) per leaflet, at the proximal margin 10 – 25 mm from the apex and at the distal margin 3 – 10 mm from the petiolule

Morphology Reproductive morphology Inflorescences

Inflorescence a congested, axillary or terminal cluster of 1 to several panicles, to 16 cm long, puberulous, hairs to 0.4 mm long, internodes 3 – 20 mm long; lateral axes to 5 cm long, 10 – 12 flowers per cm

Morphology Reproductive morphology Flowers

Flowers: floral bract inserted at base of pedicel, caducous, ovate, 5 × 3.5 mm, densely puberulous outside, sparsely puberulous inside, hairs to 0.2 mm long; pedicel 5 – 10 mm long, densely puberulous, dense light-coloured hairs to 0.1 mm long mixed with dark brown hairs to 0.4 mm long; bracteoles 2, elliptic, 6 – 7 × 5 – 6 mm, densely puberulous outside, dense light-coloured hairs to 0.1 mm long mixed with sparse dark brown hairs to 0.3 mm long, sparsely puberulous inside, centre inside glabrous; receptacle 1 mm high, 2 mm diam. at top, glabrous; sepals 5, glabrous, narrowly triangular, 4 × 1 mm, apex acute; petals 5, alternate to sepals, glabrous; adaxial petal white, claw 5 – 6 mm long, blade bilobed, 6 – 7 mm high × 10 – 12 mm wide; the other 4 petals 3.5 × 0.8 mm, apex acute; stamens 3, inserted alternate to the 4 small petals; filaments glabrous, 10 – 12 mm long; anthers glabrous, 2.5 mm long; 6 staminodes, filiform, to c. 1 mm long, inserted on a staminodal tube c. 0.8 mm long, tapering towards the top, encircling ¾ of the ovary stipe opposite the large petal; ovary 3 × 1.5 × 0.5 mm, 4 – 5 ovules, margins densely hirsute, hairs to 0.8 mm long, sides glabrous; stipe 1 mm long; style 11 – 13 mm long, lower part hirsute, upper part glabrous, stigma capitate

Morphology Reproductive morphology Fruits

Fruits oblong-rectangular, brown, dull, glabrous, 13 – 16 × 5 – 6 cm, valve 3 mm thick, beak 2 – 3 mm long, sutures not winged; 2.5 – 3 longitudinal ridges running from the base to the apex, parallel to and at 0.3 – 3 cm distance to the upper suture

Seedling

Seedlings: hypocotyl 3 – 6 cm long, epicotyl 8 – 11 cm long; first two leaves opposite, petiole and rachis 12 – 18 mm long, petiolules 1 mm, 1 pair of leaflets 10 – 12 × 3 – 4 cm (in reality 2 pairs of leaflets, lowest pair reduced to < 3 mm long)

Distribution

Gilbertiodendron bambolense is endemic to Congo (Kinshasa) (Map 12).

Ecology

Gilbertiodendron bambolense occurs in evergreen rain forest on well-drained soil, at 400 – 800 m asl.

Conservation

Gilbertiodendron bambolense is assessed here according to IUCN criteria as Least Concern (Table 1).

Note

bambolense. However, the description in this flora applies to G. ogoouense s.l.

The name Macrolobium bambolense Louis appears in Louis & Fouarge (1949: 9 – 11, 14, 16) and on some of the specimens, e.g. Louis 11208 (BR, K) and Louis 11234 (BR, K): Macrolobium bambolense Louis sp. nov.; det.: 9 Aug. 1949. However, J. Louis never published this name according to the Code; no Latin description was published. The only clear difference between Gilbertiodendron bambolense and G. ogoouense is in the number of pairs of leaflets: 4 – 7 pairs of leaflets versus (2 –) 3 pairs; and consequently in the length of the rachis. The inflorescences and flowers of both species are more or less identical. However, the flower bract of G. bambolense is 5 mm long; while that of G. ogoouense is 3 mm long. G. bambolense has denser, longer and darker hairs on the pedicel and bracteoles, compared to G. ogoouense..

The species epithet of Gilbertiodendron bambolense refers to the Bambole (BaMbole, Mbole) ethnic group from the centre of Congo (Kinshasa).

Gilbertiodendron bambolense is related to G. sulfureum. G. bambolense is a large tree from forest on well-drained soil, while G. sulfureum is a small to medium-sized tree from swamp forest. The twigs and rachis of G. bambolense are glabrescent to glabrous, if hairs are present they are sparse and to 0.3 mm long. The twigs and rachis of G. sulfureum are puberulent with hairs to 0.2 mm long. The leaves of G. bambolense have 4 – 7 pairs of leaflets. The leaves of G. sulfureum have more pairs of leaflets, 4 – 9 (– 10) pairs. The leaflets of G. bambolense are glabrous beneath; the midrib beneath is glabrescent to glabrous. The leaflets of G. sulfureum are sparsely puberulent to glabrescent beneath. The bracteoles of G. bambolense are dark brown in colour when dried; the bracteoles of G. sulfureum are yellowish light brown when dried.

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: threatened. Confidence: confident