Parapiptadenia Brenan, Kew Bull. 17(2): 228. 1963.

Figs 172, 173, 179

Type.

Parapiptadenia rigida (Benth.) Brenan [≡ Piptadenia rigida Benth.]

Description.

Trees; indumentum composed of simple trichomes; brachyblasts absent; branches and leaves unarmed, not odoriferous. Stipules present or absent. Leaves bipinnate; extrafloral nectaries on the petiole, and usually between the distal pair of pinnae and leaflets; pinnae 1-8 pairs, opposite; leaflets (1) 2-26 pairs, opposite, elliptic to oblong. Inflorescence units cylindrical spikes, solitary, axillary or supra-axillary to coevally developing leaves. Flowers 5-merous, reddish, rarely yellowish; calyx gamosepalous, campanulate; corolla gamopetalous, campanulate to tubular; stamens 10, anthers with an apical gland; pollen in 8, 12 or 16-grained polyads; ovary included in the corolla. Fruit a legume, flat-compressed, valves undulate above the seeds (rarely plane). Seeds flat-compressed, dark, winged, pleurogram absent.

Chromosome number.

2 n = 26 (Goldblatt 1981a).

Included species and geographic distribution.

Six species, four from north-eastern Brazil, one extending also to south-eastern Brazil; and two occurring in southern Brazil, Argentina, Paraguay, and Uruguay, one of which also reaches Bolivia, western Brazil and Peru (Fig. 179).

Ecology.

Sub-tropical forests, rainforests, seasonally dry tropical forests and woodlands.

Etymology.

From para (Greek = next to) and Piptadenia piptadenia, in reference to the close taxonomic relationship to the genus Piptadenia (Brenan 1963b).

Human uses.

Parapiptadenia rigida has medicinal properties, is used as fodder, timber, firewood, an ornamental, as a source of saponins, gum, tannins, cellulose, for paper production, and for ecological restoration (Burkart 1979; Carvalho 2003).

Notes.

In addition to Anadenanthera Speg., Parapiptadenia is the only segregate from Piptadenia that was confirmed as monophyletic (Jobson and Luckow 2007; Simon et al. 2016; Ribeiro et al. 2018; Borges et al. 2022). The genus commonly includes plants with reddish flowers, although these are yellow or cream in a few species [e.g., Pa. rigida (Benth.) Brenan], and legumes with undulate valves above the seeds. Most genera in the Stryphnodendron clade have yellow or cream inflorescences and either follicles or indehiscent fruits, except for Stryphnodendron and Naiadendron, which include some species with reddish inflorescences and legumes, respectively.

Taxonomic references.

Brenan (1963b); Caccavari (2002); Lewis (1993); Lima and Lima (1984); Vaz and Lima (1980).