Biancaea Tod., Nuovi Gen. Sp. Orto Palermo: 21. 1860, descr. emended E. Gagnon & G. P. Lewis

Gagnon, Edeline, Bruneau, Anne, Hughes, Colin E., de Queiroz, Luciano Paganucci & Lewis, Gwilym P., 2016, A new generic system for the pantropical Caesalpinia group (Leguminosae), PhytoKeys 71, pp. 1-160 : 44-46

13. Biancaea Tod., Nuovi Gen. Sp. Orto Palermo: 21. 1860, descr. emended E. Gagnon & G. P. Lewis Figs 20G-J , 22

Campecia Adans. 1763; no type species designated, and no species names ever published in this genus. It is thus not possible to apply this name which is rejected against Biancaea .

Caesalpinia sect. Sappania DC. 1825.

Diagnosis.

Biancaea is closely related to Mezoneuron , differing principally in its fruit, a coriaceous, laterally compressed, wingless, dehiscent pod (except Biancaea decapetala , which has somewhat inflated, boat-shaped pods, often with a narrow wing or ridge along the upper suture). In contrast, Mezoneuron has chartaceous, coriaceous or ligneous pods, which are also laterally compressed, but indehiscent, and with a wing along the upper suture. In addition, the ovary of Biancaea species always has a velvety indumentum (vs. glabrous to pubescent in Mezoneuron ).

Type.

Biancaea scandens Tod. ≡ Biancaea decapetala (Roth) Deg.

Emended description.

Lianas, climbing or trailing shrubs (1-3 m), or small trees (2.5-10 m), armed with short, slightly recurved prickles, scattered along the branches; young shoots pubescent or glabrescent. Stipules lanceolate-oblong to broadly-ovate, sometimes amplexicaul at base, 3-4 mm to 4.5 cm long, caducous or sub-persistent to persistent. Leaves alternate (except in Biancaea oppositifolia ), bipinnate, ending with a pair of pinnae, rachis pubescent (glabrous in Biancaea oppositifolia ), armed with pairs of prickles at the base of each pinna, sometimes also scattered on the rachis; pinnae in 4-19 opposite to alternate pairs; leaflets opposite to alternate, in 5-20 pairs per pinna, blade membranous, eglandular, glabrous to pubescent, 10-35 × 4-15 mm (4-10 × 1.5-4.5 cm in Biancaea oppositifolia ), oblong-elliptic, apex acute, obtuse, rounded to emarginate, base asymmetric. Inflorescences erect, showy, terminal or axillary racemes or panicles; rachis eglandular, pubescent, unarmed or with a few scattered prickles, mainly near the base; bracts ovate-lanceolate, acuminate, 2-8 mm long, caducous. Flowers bisexual, zygomorphic; calyx with a short hypanthium and 5 sepals, the lower sepal cucullate and covering the other 4 in bud, sepals pubescent (except in Biancaea sappan ), caducous, but the hypanthium persisting as a calyx ring around the pedicel as fruits mature; petals 5, free, yellow to white, eglandular, the claws pubescent; the median petal smaller than the other 4, and inrolled towards the centre, lateral petals oblong, obovate to spathulate, 4-10 × 2-8 mm; stamens 10, filaments densely pubescent (most evident at the base), eglandular, 10-15 mm long; ovary densely velutinous. Fruit a coriaceous, glabrous, eglandular, oblong-elliptic to obovate, dehiscent, wingless, laterally compressed (but somewhat inflated and often with a narrow wing along the upper suture in Biancaea decaptala ), 4.5-10 × 2-4 cm, 2-8-seeded pod, usually much broader at the rounded to truncate apex, which terminates in a sharp beak. Seeds flat, elliptic, ovoid to orbicular, c. 2 cm in diameter, black or brown.

Geographic distribution.

A genus of six species widespread across southern Asia, from India, to Myanmar (Burma), Thailand, Cambodia, Vietnam, south China, Japan, the Philippines, and the Malay Peninsula and Archipelago, one species endemic to Sabah (near Sandakan). Biancaea decapetala , native to Asia, has been widely introduced across the tropics as a hedge plant or ornamental and is considered to be invasive in South Africa and Hawaii.

Habitat.

Primary forest and forest margins, grasslands, scrub vegetation, riverine habitats, secondary thickets and clearings. From the coast to mountain slopes.

Etymology.

Unknown.

Notes.

Based on the study of Gagnon et al. (2013), Molinari-Novoa et al. (2016) provided some, but not all, of the required nomenclatural transfers to the genus Biancaea . Furthermore, they did not emend the description of the genus, as provided here.

References.

Hattink (1974); Vidal and Hul Thol (1976); Jansen (2005); Brummitt et al. (2007); Chen et al. (2010a); Molinari-Novoa et al. (2016).

Figures

Figure 20. Moullava spicata (Dalzell) Nicolson. A inflorescences B fruit (P. Awale, Flowers of India (http: // www. flowersofindia. net /), Maharashtra, India, unvouchered) C flowers (M. Sanjappa, India, unvouchered). Guilandina bonduc L. D young fruits (F. Starr and K. Starr, Starr Environmental (http: // www. starrenvironmental. com / images / species /? q = Caesalpinia + bonduc), Florida, USA, unvouchered) E fruits with mature seeds (G. P. Lewis, Madagascar, Du Puy et al. M 665 (K )) F inflorescence (M. Sanjappa, India, unvouchered). Biancaea decapetala (Roth) O. Deg. G fruits with seeds H fruit with thickened suture (C. E. Hughes, Ancash, Peru, Hughes et al. 2227 (FHO )) I inflorescence (E. Gagnon, Ancash, Peru, Hughes et al. 3055 (MT )). Biancaea godefroyana (Kuntze) Molinari, Mayta & Sanchez Och. J inflorescences and fruits (F. Xaver, Wikicommons (https: // commons. wikimedia. org / wiki / File: Caesalpinia _ godefroyana _ 1. jpg), Cambodia, unvouchered).

Figure 22. Biancaea decapetala (Roth) O. Deg. A flowering branchlet and foliage B, C leaflets viewed from above and below, respectively D flower with parts separated, and centre of flower enlarged E calyx three views F lateral petal G median petal H stamen I anther J gynoecium K fruits L seed. A from Rutherford-Smith 11062 B, C from White 2478 D-J from Chase 4564 K, L from Myre 2528. Drawn by D. Erasmus, originally published in Flora Zambesiaca, vol. 3 part 2, page 182, figure 3.2.39 (2007).