Tetrapleura Benth., J. Bot. (Hooker) 4: 345. 1841.

Bruneau, Anne, de Queiroz, Luciano Paganucci, Ringelberg, Jens J., Borges, Leonardo M., Bortoluzzi, Roseli Lopes da Costa, Brown, Gillian K., Cardoso, Domingos B. O. S., Clark, Ruth P., Conceicao, Adilva de Souza, Cota, Matheus Martins Teixeira, Demeulenaere, Else, de Stefano, Rodrigo Duno, Ebinger, John E., Ferm, Julia, Fonseca-Cortes, Andres, Gagnon, Edeline, Grether, Rosaura, Guerra, Ethiene, Haston, Elspeth, Herendeen, Patrick S., Hernandez, Hector M., Hopkins, Helen C. F., Huamantupa-Chuquimaco, Isau, Hughes, Colin E., Ickert-Bond, Stefanie M., Iganci, Joao, Koenen, Erik J. M., Lewis, Gwilym P., de Lima, Haroldo Cavalcante, de Lima, Alexandre Gibau, Luckow, Melissa, Marazzi, Brigitte, Maslin, Bruce R., Morales, Matias, Morim, Marli Pires, Murphy, Daniel J., O'Donnell, Shawn A., Oliveira, Filipe Gomes, Oliveira, Ana Carla da Silva, Rando, Juliana Gastaldello, Ribeiro, Petala Gomes, Ribeiro, Carolina Lima, Santos, Felipe da Silva, Seigler, David S., da Silva, Guilherme Sousa, Simon, Marcelo F., Soares, Marcos Vinicius Batista & Terra, Vanessa, 2024, Advances in Legume Systematics 14. Classification of Caesalpinioideae. Part 2: Higher-level classification, PhytoKeys 240, pp. 1-552 : 1

Tetrapleura Benth., J. Bot. (Hooker) 4: 345. 1841.

Figs 104 , 105 , 106 , 108

Type.

Tetrapleura thonningii Benth., nom. illeg. [= Tetrapleura tetraptera (Schumach. & Thonn.) Taub. (≡ Adenanthera tetraptera Schumach. & Thonn.)]

Description.

Unarmed trees or shrubs 8-25 m tall (Fig. 104D ), to 60-90 cm in diameter, usually lacking buttresses but occasionally with short, sharp buttresses; bark smooth, dark brown, very thin, slightly spongy; brachyblasts absent. Stipules not observed. Leaves bipinnate, 10-40 cm long, foliar glands absent; pinnae 2-10 (15) pairs per leaf, opposite to subopposite; leaflets alternate, 6-26 per pinna, petiolulate. Inflorescences of solitary or paired spiciform axillary racemes, 5-10 cm long (Fig. 105C ), usually borne on older wood and immersed in the foliage, but the leaves sometimes suppressed and the racemes forming a pseudopanicle. Flowers hermaphrodite, pedicellate, the pedicel abscising with the flowers, small persistent triangular bracts at the base of each flower; calyx conical, shallow, 5-toothed, valvate in bud; petals 5, free, linear-lanceolate, cream to pale pink aging orange-red, valvate in bud (Fig. 105B,C ); stamens 10, free, slightly exserted above the petals, filaments white, anthers with a caducous apical gland; pollen in 16-grained calymmate polyads; ovary oblong, sessile, glabrous, stigma porate. Fruits straight, oblong, woody, indehiscent, 10-20 cm long, four-winged with flattened sutural ribs and longitudinal wings running down the centre of the valve (Fig. 106E ), each wing to 1 cm broad, two of the wings filled with pulp, cruciform in cross-section, dark brown, pods internally septate between the seeds with spongy, fibrous endocarp. Seeds inserted transversely, brown, smooth, unwinged, testa hard, pleurogram present.

Chromosome number.

2 n = 26 ( Fedorov 1969).

Included species and geographic distribution.

Two species in tropical Africa, in the Guineo-Congolese forest from Senegal to Sudan, Uganda, and Kenya, south to Angola and Tanzania (Fig. 108 ).

Ecology.

Common in secondary forest but growing best in undisturbed rainforest; high forest zones, riverine forests, southern savanna woodland, and as forest outliers in the African plains.

Etymology.

From the Greek, tetra (= four) and pleura (= ribs), referring to the four ribs on the fruits.

Human uses.

A valued forest species for its fragrant fruits and seeds which are used to season food. The fruits, seeds, leaves, and bark are all used in folk medicine to treat a wide variety of ailments. The chemistry of the fruits has been studied and found to be a potential treatment for diabetes and to reduce inflammation ( Orwa et al. 2009; Kuate et al. 2015).

Notes.

Tetrapleura differs from Amblygonocarpus in Hoffmannseggia minor characters as described below under Amblygonocarpus . Although they might be treated as a single genus, the two genera tend to be ecologically distinct. Tetrapleura is a rainforest tree that only occasionally moves into the savanna as a forest outlier whereas Amblygonocarpus is a true inhabitant of savannas and deciduous forests.

Taxonomic references.

Brenan (1959) with illustration; Kemigisha et al. (2018).

Figures

Figure 104. Habit and growth form in the Adenanthera clade A Xylia xylocarpa var. kerrii (Craib & Hutch.) I. C. Nielsen scaly bark B Xylia torreana Brenan canopy C Pentaclethra macroloba (Willd.) Kuntze trunk showing buttresses D Tetrapleura tetraptera (Schumach. & Thonn.) Taub. canopy (Harris 9659) E Amblygonocarpus andongensis (Welw. ex Oliv.) Exell & Torre pale grey, scaly bark (Catarino 2067) F Pseudoprosopis gilletii (De Wild.) Villiers liana with leaves and lignified tendrils (Texier 1558) G Adenanthera pavonina L. thin scaly bark H habit I Amblygonocarpus andongensis (Welw. ex Oliv.) Exell & Torre growing in savanna (Coates Palgrave M 806). Photo credits A Dechaphaetkrathok B F du Randt C D DeMelo D DJ Harris E L Catarino F N Texier G, H Shelbyfarmer I M Coates Palgrave.

Figure 105. Flowers and inflorescences in the Adenanthera clade A Adenanthera pavonina L. inflorescence B, C Tetrapleura tetraptera (Schumach. & Thonn.) Taub. (Harris 9663) B reflexed petals and white filaments on the flowers C racemose inflorescence D Xylia hoffmannii (Vatke) Drake umbellate inflorescence (Ratovoson 838) E Calpocalyx klainei Pierre ex Harms inflorescence (Texia 976) F Pseudoprosopis bampsiana Lisowski flower detail showing pseudopedicels (Bidault 2515) G, H Pentaclethra macroloba (Willd.) Kuntze G inflorescences congested at the ends of branches H close-up of the inflorescence showing the long filamentous staminodes. Photo credits A CheongWeei Gan B, C DJ Harris D F Ratovoson E N Texia F E Bidault G, H D Cardoso.

Figure 106. Fruits and seeds in the Adenanthera clade A Adenanthera pavonina L. dehisced fruits with exposed persistent red seeds B Amblygonocarpus andongensis (Welw. ex Oliv.) Exell & Torre Indehiscent four-angled fruits (Catarino 2067) C Pseudoprosopis fischeri Harms young fruit (Bingham 8055) D Xylia xylocarpa var. kerrii (Craib & Hutch.) I. C. Nielsen young dolabriform pod E Tetrapleura tetraptera (Schumach. & Thonn.) Taub. immature winged, indehiscent pod (Harris 9659) F Pentaclethra macrophylla Benth. pod and recalcitrant seeds G, H Calpocalyx ngouniensis Pellegr. woody valves from dehisced pod (Texier 695). Photo credits A Shelbyfarmer B L Catarino C MG Bingham D B Peroth E DJ Harris 9659 F CJ Porto, Fundacion Tierra Iberica G H N Texier.

Figure 108. Distribution of Tetrapleura based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.