Parkinsonia
Sp. Pl. 1: 375. 1753.
Trees or shrubs, armed or unarmed. Stems and branches green or yellowish green, erect, glabrous or strigulose, glabrescent. Leaves clustered, alternate from spurs, even-bipinnate, sometimes appearing pinnate; stipules present, caducous, minute, or spinescent; petiolate or petiole obsolete; pinnae 2(or 3)[4], glands linear, minute, in sparse to dense patches between leaflets, in leaflet axils, or surrounding pulvini; leaflets 2–76, alternate, subopposite, or opposite, blade margins entire, surfaces sparsely pubescent abaxially, glabrate or sparsely pubescent adaxially. Inflorescences 2–15-flowered, axillary, racemes [corymbiform]; bracts and bracteoles present. Flowers caesalpinoid; calyx actinomorphic, nearly aposepalous, nearly regular, lobes 5; corolla yellow, erose-margined, glabrous except claw pubescent; stamens 10, distinct or monadelphous, villous proximally, much longer than anthers; anthers basifixed. Fruits legumes, stipitate, compressed or subterete, sometimes torulose, oblong to linear, indehiscent, glabrous, glabrate, or pubescent. Seeds 1–5, oblong to suborbiculate in silhouette, 4–7 mm wide; hilum apical or subapical. x = 14.
Distribution
s, w United States, Mexico, West Indies, Central America, introduced in South America, Asia, Africa, Australia.
Discussion
Species ca. 12 (4 in the flora).
Taxa referable to Parkinsonia usually have been treated in Cercidium and Parkinsonia (C. S. Sargent 1889; I. M. Johnston 1924; L. D. Benson 1940; A. M. Carter 1974, 1974b) or within a broad Parkinsonia (S. Watson 1876; J. P. M. Brenan 1963; D. Isely 1975; R. M. Polhill and J. E. Vidal 1981; J. A. Hawkins 1996). Molecular evidence from the chloroplast genome indicated that, together, Cercidium and Parkinsonia form a strongly supported monophyletic group (E. M. Haston et al. 2005) and a broad circumscription is adopted here.
Selected References
None.
Key
| 1 | Pinna rachillas (100–)150–600 mm, narrowly winged; leaflets 40–76, alternate, subopposite, or opposite (usually all on same rachilla); raceme axis 8–18 cm. | Parkinsonia aculeata |
| 1 | Pinna rachillas 1.5–40 mm, not winged; leaflets 2–16, opposite; raceme axis 0.4–3.8 cm. | > 2 |
| 2 | Nodal spines absent, branch tips often spinescent; leaves appearing pinnate; petiole obsolete; leaflets (6–)12–16; rachillas with glandular patches surrounding leaflet pulvini or, at least, on opposing sides; sepal adaxial surfaces pubescent; petals light yellow, except adaxial one white or cream-yellow, not orange-dotted; ovaries densely sericeous; legumes constricted between seeds. | Parkinsonia microphylla |
| 2 | Nodal spines present; leaves evidently bipinnate; petiole 1.6–3.5 mm; leaflets 2–6 (or 8); rachillas with glandular patches on adaxial side, not surrounding leaflet pulvini; sepal adaxial surfaces glabrous; petals deep yellow, adaxial one often orange-dotted basally; ovaries glabrate or sericeous; legumes either not constricted between seeds or irregularly and indistinctly torulose. | > 3 |
| 3 | Stems pale green; ovaries glabrate; legumes not constricted between seeds; Arizona, California, Nevada. | Parkinsonia florida |
| 3 | Stems dark to olive green; ovaries sericeous or glabrate; legumes irregularly and indistinctly torulose; s Texas. | Parkinsonia texana |