Osodendron dinklagei (Harms) E.J.M. Koenen, 2022

Koenen, Erik J. M., 2022, Osodendron gen. nov. (Leguminosae, Caesalpinioideae), a new genus of mimosoid legumes of tropical Africa, PhytoKeys 205, pp. 453-470 : 453

2. Osodendron dinklagei (Harms) E.J.M. Koenen comb. nov.

Fig. 3A-F

Albizia dinklagei (Harms) Harms, Bot. Jahrb. Syst. 53(3-5): 455, in obs. 1915.

Pithecellobium dinklagei (Harms) Harms, Notizbl. Bot. Gart. Berlin-Dahlem 8: 145. 1922.

Cathormion dinklagei (Harms) Hutch. & Dandy, Fl. W. Trop. Afr. [Hutchinson & Dalziel] 1: 364. 1928; Hutchinson & Dandy in Kew Bull. 401. 1928.

Samanea dinklagei (Harms) Keay, Kew Bull. 8(4): 488. 1954.

Basionym.

Mimosa dinklagei Harms, Bot. Jahrb. Syst. 26(3-4): 253. 1899.

Type material.

Liberia, Grand Bassa, 21 May 1897, Dinklage 1827 (holotype: B†, isotype: K! [K000044068]).

Description.

Tree, up to 30 m tall, twigs with rows of lenticels and becoming shallowly grooved with age. Twigs, stipules, perulate resting buds, all leaf-axes and peduncles covered in a densely villose ferruginous indumentum. Foliage consisting of very finely divided bipinnately compound leaves, the tiny leaflets ciliate and somewhat discolourous. The inflorescences consisting of sub-spherical capitula emerging from axillary fascicles of coeval leaves, sometimes in compound ramiflorous pseudoracemes with the leaves not fully developing and caducous. Stipules narrowly deltoid or lanceolate to linear 3.5-4.3(-9) × ca. 1 mm, caducous leaving conspicuous glabrous scars, perulae deltoid, ca. 2 × 1.5 mm. Leaves with 10-34 pairs of pinnae, often with one or a few much reduced pinnae at the base, petiole 5-11 mm, pulvinate and adaxially flattened at the base, usually with a sessile or shortly stipitate cupular nectary 0.5-0.7 mm in diameter just below the lowermost pinna pair, rachis grooved and adaxially canaliculate although obscured by dense indumentum, with a 1-1.5 mm long deciduous mucro, 6.5-16(-21) cm, with 3-8(-11) interpinnal subsessile cupular nectaries apically, these sometimes button-shaped and on a 0.7 mm long stipe, pinnae obscurely pulvinate, with an adaxial ridge and a tiny 0.3-0.4 mm long mucro at the apex, 1.0-2.5(-4.5) cm, usually without nectaries, except on larger leaves (of juveniles or coppice shoots) with cupular nectaries between the upper 1-3 leaflet pairs, pinnae with (9-)27-40(-48) leaflet pairs, the abaxial leaflet of the lowermost pair usually reduced to a paraphyllidium, leaflets inequilaterally linear, sessile and pulvinate, with strongly oblique base and acute apex, 0.8-3 × 0.2-0.8 mm, venation obscure on the adaxial surface, palmately-pinnate brochidodromous, with three secondary veins emerging from the base next to the clearly stronger mid-rib on the adaxial side, 2-3 further secondary veins on each side and sparse reticulate tertiary venation. Capitula 1-3 per leaf axil, ca. 40-60-flowered, on peduncles 1.8-3.5(-4.1) cm, dimorphic with 1(-3) central flower(s) that are more robust and with a longer, exserted staminal tube. Peripheral flowers ca. 0.7 mm broad at the base, the basal ones on a pedicel of ca. 0.4-0.6 mm, the others sub-sessile to sessile closer to the apex. Calyx slenderly campanulate, green, 5-merous, 1.6-3.1 mm long, densely puberulous on outer surface, the deltoid lobes ca. 0.4 × 0.4 mm, corolla green, 4- or 5-merous, 3-5.5 mm long, pubescent, the lobes 1.8-2 mm long, stamens 10-14, filaments white, 14 mm long, basally fused into a tube ca. 3 mm long, anthers light yellow, basifixed, pollen released in 32-celled polyads, pistil ca. 18 mm long with a sessile ovary ca. 2.5 mm long, puberulent on upper half with white hairs, stigma shallowly funnel-shaped. Central flower(s) similar to peripheral flowers, but ca. 1.8 mm broad at the base, calyx 2.0-2.4 mm long, corolla ca. 4.5 mm long, staminal tube ca. 6 mm long (i.e. the stamens are approximately the same length, but fused for a greater part than in peripheral flowers). Fruit an indehiscent woody pod up to 13-18 × 2-2.2(-2.5) × 0.3-0.6 cm, straight or slightly curved and with uniformly thick valves, except for the distinctly thickened margins, not swollen over the seeds, 16-24 seeded when well-fertilised, seeds rounded elliptical, only slightly laterally compressed, greenish light brown, 6-7.5 × 4-5 × 3-3.5 mm when dry, with a hard testa and an elongate closed pleurogram 5-6 × 2-2.5 mm.

Distribution.

Upper Guinea, from Guinea-Bissau to Ghana (Fig. 3G ).

Ecology.

Rainforest, gallery forest, wooded grassland, edges of mangrove swamp.

Representative specimens examined.

Guinée-Bissau: Espírito Santo 1747 (K) & 1864 (K) & 1871 (K) & 2697 (K). Sierra Leone: X. van der Burgt 1994 (K).

Figures

Figure 3. A-F Osodendron dinklagei: A trunk of adult specimen in terra firme forest B foliage C detail of pinnae D detail of resting bud and petiolar nectary E inflorescence F pods G distribution map of O. dinklagei and O. leptophyllum as per the legend based on data from Gbif. org H-K O. leptophyllum: H trunk I bipinnate leaf J close-up of leaflets K twig and pods. Images: A-D, F William Hawthorne (FHO) E Xander van der Burgt (K) H-J David Harris (E) K Paul Latham H-K from www. africanplants. senckenberg. de.