Shrubs to 6 m, much-branched. Stems appressed-puberulent when young. Leaves 5–15 × 2–6 cm; stipules distinct, relatively small; leaflet blades elliptic to obovate or ovate, 15–30 × 10–20 mm, base cuneate, apex usually emarginate, mucronate, surfaces appressed-pubescent abaxially, glabrate adaxially. Peduncles 2–4 cm. Racemes 4–6 × 3–4 cm; bracteoles linear, 2 mm. Pedicels 5–8 mm in flower, 10–12 mm in fruit. Flowers: calyx actinomorphic or slightly zygomorphic, 5–8 mm, lobes linear to deltate, 1–3 mm; banner 16–20 × 10–15 mm; wings equaling or shorter than keel; style pubescent apically. Fruits pale greenish brown, sometimes reddish proximally, 5–8 × 3 cm, papery. Seeds 3–5 mm. 2n = 16 (Europe).
Phenology: Flowering late spring–early summer.
Habitat: Roadside scrub, disturbed ground.
Elevation: 10–2500 m.
Distribution
Introduced; Ont., Calif., Colo., Conn., Kans., Mass., Mich., Nev., N.J., N.Mex., N.Y., Ohio, Okla., Pa., R.I., Utah, W.Va., Europe, w Asia, n Africa (Algeria), introduced also in s South America (Argentina).
Discussion
Colutea arborescens is cultivated as an ornamental for its flowers and large, conspicuous fruits. In addition to C. arborescens, C. × media Willdenow (C. arborescens Linnaeus × C. orientalis Miller) also is cultivated and may occur as a relic. The hybrid has a brownish red or dark orange corolla and a fruit that is dehiscent apically.
Selected References
None.