Herbs, perennial, shrubs, or trees, armed or unarmed. Stems spreading, ascending, or erect, glandular or eglandular, glabrous or pubescent. Leaves alternate, odd-bipinnate; stipules present, caducous or persistent, ovate-lanceolate to orbiculate; petiolate or short-petiolate; pinnae 2–15 pairs, alternate, opposite, or subopposite; stipels present; leaflets 7–23, opposite, blade margins entire, sometimes revolute, surfaces glabrous or pubescent, often glandular-punctate with conspicuous black, sessile glands along margins, these sometimes sunken in sinuses of crenulated margin. Inflorescences 6–40+-flowered, axillary or terminal, racemes; bracts present, persistent or caducous. Flowers caesalpinioid, monomorphic, androecium and gynoecium free, not cupped in lower sepal; calyx zygomorphic, persistent, margins fimbriate-glandular, lobes 5; corolla yellow (or orange, red, or white in ornamental plants); stamens 10, distinct; anthers versatile. Fruits legumes, sessile, flattened, straight or falcate, lanceolate-oblong, elastically dehiscent, subligneous, leathery, glandular or eglandular, pubescent or glabrous. Seeds (1–)3–6, brown, ovate. x = 12.

Distribution

w, s United States, Mexico, Central America, South America, introduced in Africa, Australia.

Discussion

Species ca. 30 (4 in the flora).

In some species of Caesalpinia and allied genera, such as Erythrostemon, stalked glands in the shape of wine glasses have been called pixie-cup glands.

Selected References

None.

Lower Taxa

Erythrostemon caudatus, Erythrostemon gilliesii, Erythrostemon mexicanus, Erythrostemon phyllanthoides

Key

1	Leaflets 3–7 pairs on lateral pinnae, 8–20 pairs on terminal pinna.	Erythrostemon caudatus
1	Leaflets on lateral and terminal pinnae ± equal in number (2–11 pairs).	> 2
2	Filaments 70–95(–120) mm, much longer than banner; inflorescence axis densely stipitate-glandular; legumes 8–10.8 cm.	Erythrostemon gilliesii
2	Filaments 9–13 mm, shorter to longer than banner; inflorescence axis eglandular; legumes 2.5–7.5 cm.	> 3
3	Shrubs or trees, 1–6 m, not clonal; pinnae 2–4(or 5) pairs, leaflets (2 or)3–5(or 6) pairs, blades obovate-elliptic, 10–35 mm; calyx densely pubescent on inner surface, inflorescence moderately pubescent or glabrous; legumes 4.4–7.5 cm; seeds (1 or)2–5.	Erythrostemon mexicanus
3	Herbs or shrubs, 0.3–0.8 m, clonal; pinnae 3 or 4 pairs; leaflets 2 or 3 pairs, blades obovate to elliptic, 4–11 mm; base of calyx and apex of pedicel stipitate-glandular, inflorescence otherwise eglandular; legumes 2.5 cm; seeds 1 or 2.	Erythrostemon phyllanthoides