Trees or shrubs armed by spinescent stipules and stipella. Leaves bipinnate, not sensitive to the touch; Inflorescences composed of pedunculate glomerules or corymbs which are aggregated into terminal or axillary panicles. Flowers uniform, bisexual, pentamerous. Stamens numerous, united in a tube at the base. Ovary solitary. Seeds brown or blackish, wingless, obovate or asymmetric, with areole.
Asia: present Asia-Tropical:, Sri Lanka (Sri Lanka present); Thailand (Thailand present) S Vietnam: present tropical and subtropical America: present
A genus of c. 20 species, indigenous in tropical and subtropical America. Three Asian species, P. nitidum (Sri Lanka), P. tenue (Thailand), and P. vietnamense (S Vietnam), are provisionally referred to this genus, but they lack the aril, and may belong to the genus Havardia (cf. Nielsen, l.с.); two species are introduced to Malesia, one an old introduction and common, and one newly established.
Formerly, the major part of the species now referred to Archidendron and some of the species of Albizia were referred to this genus. If these discordant elements would be united into one genus, this would be the only genus of the, bipinnate, tribus Ingeae, and Pithecellobium would not be the oldest name, both Zygia and Albizia being older. For taxonomic reasons [Nielsen, l.с. and ] Pithecellobium is restricted to comprise the New World species, characterized by spinescent stipules, uniform flowers and funicular aril.
Benth. - in Lond. J. Bot. 1844: 195
Benth. - in Trans. Linn. Soc. 1875: 570
Kosterm. - in Bull. Organ. Natuurw. Onderz. Indon. 1954: 7
Benth. & Hook. f. - in Gen. Pl. 1865: 597
Nielsen - in Polhill & Raven (eds.), Adv. Leg. Syst. 1. 1981: 184
Mohlenbr. - in Reinwardtia. 1963: 438
Hutch. - in Gen. Fl. Pl. 1964: 296
Taub. - in E. & P., Nat. Pflanzenfam. 3. 1891: 104