Senna surattensis

Shrubs or trees, to 4(–6) m. Leaves mesophyllous, 8–18 cm, finely, densely hairy; stipules caducous; extrafloral nectaries 1–3, between first only, or also subsequent, leaflet pairs, sessile; leaflet pairs 6–10, blades obovate, obovate-elliptic, oblanceolate-obtuse, 20–50 × 8–20 mm. Racemes usually 5–21-flowered; bracts late caducous. Pedicels 16–25 mm. Flowers slightly asymmetric; calyx greenish; corolla pale yellow, longest petal 16–24 mm; androecium heterantherous, stamens 10, staminodes 0; anthers of 9 short stamens 4–5.2 mm, of 1 long stamen 4.5–6.5 mm, dehiscing by 2 pores, apical appendage 0; gynoecium slightly incurved, ovules 18–30; ovary slightly hairy; style slightly incurved. Legumes somewhat pendulous, flat, slightly curved, 70–100 × 11–15 mm, slightly corrugated over seeds, indehiscent. Seeds dark reddish brown, oblong-ellipsoid.

Phenology: Flowering late winter–late fall.
Habitat: Habitat unknown.
Elevation: 0–10 m.

Introduced; Fla., Asia, Africa, Pacific Islands, Australia, introduced also in West Indies (Bahamas, Puerto Rico, Saint Vincent).

Discussion

Senna surattensis has been cultivated for centuries as an ornamental in tropical regions, making inference about its origin and native range of geographic distribution a matter of speculation (G. Bentham 1863–1878; D. E. Symon 1966; H. S. Irwin and R. C. Barneby 1982). In North America it is cultivated in California and Texas in addition to Florida (D. Isely 1998). Senna surattensis is often confused with S. multiglandulosa; they are similar in habit and widely cultivated, but S. surattensis possesses seven heterantherous stamens and three staminodes. The similar and closely related S. sulfurea (Colladon) H. S. Lewis & Barneby (with two long stamens instead of one) was considered a subspecies of S. surattensis by B. R. Randell (1989).

Selected References

None.

Lower Taxa