About four species: mostly in dry regions of S Africa, tropical America, and Oceania; one species (introduced) in China.
1. Parkinsonia aculeata Linnaeus, Sp. Pl. 1: 375. 1753.
扁轴木 bian zhou mu
Shrubs or trees, to 6 m tall, prickly, with smooth, green
bark. Leaf rachis and stipules becoming spines; pinnae 1–3
pairs, clustered at spinescent, very short rachis of leaves; rachis
of pinnae green, to 40 cm; leaflets obovate-elliptic to obovateoblong
or oblong, 2.5–8.5 × 1–3.5 mm. Racemes sparsely flowered.
Flowers yellow; pedicels 1.5–1.7 cm; bracts lanceolate.
Sepals oblong, ca. 6 mm, apex obtuse. Petals spatulate, apex
rounded, uppermost longer, ca. 11 × 6 mm. Filaments villous at
base. Legume 7.5–10.5 cm.
Cultivated in Hainan [native to tropical America; widely cultivated
in tropical regions of the world].