Senna occidentalis |
Senna bauhinioides |
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coffee senna, septicweed |
twinleaf senna |
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Habit | Herbs, perennial, bushy, to 2.2 m; branches dark green and blackish. | Herbs, perennial, to 0.4 m. Leaves slightly sclerophyllous, 1.5–5.5 cm, hairy; stipules caducous; extrafloral nectary 1, between leaflet pair, stipitate or subsessile; leaflet pairs 1, blades obliquely oblong or ovate-oblong, 8–46 × 5–16 mm. |
Leaves | mesophyllous, 11–26 cm, glabrous or glabrate; stipules caducous; extrafloral nectary 1, base of petiole, sessile or subsessile; leaflet pairs 4 or 5(or 6), blades lanceolate- or ovate-acuminate, 45–100 × 12–38 mm. |
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Racemes | usually (1 or)2–5-flowered; bracts caducous, longer than bud, often blackish green. |
1–3-flowered; bracts caducous. |
Pedicels | 8–21 mm. |
3–11 mm. |
Flowers | monosymmetric; calyx pinkish or fuscous; corolla yellow, longest petal 12–17 mm; androecium heterantherous, stamens 6, staminodes 3 + 1; anthers of middle stamens 3.2–5.2 mm, of abaxial stamens 4.9–6.6 mm, elongated beyond pores, dehiscing by U-shaped pore, apical appendage linguiform, thickened; gynoecium incurved, ovules 40–60; ovary densely hairy; style slightly incurved. |
monosymmetric; calyx caducous, yellowish to pale green; corolla yellow, longest petal 5–10 mm; androecium not heterantherous, stamens 7, staminodes 3; anthers to 1.8–2.8 mm, dehiscing by 1 apical pore, apical appendage 0; gynoecium nearly linear, ovules 22–36; ovary densely hairy; style incurved, to 1.5 mm, distally dilated. |
Legumes | ascending, flat, slightly curved or straight, linear, 80–135 × 6.5–9.5 mm, corrugated over seeds, dehiscent. |
erect, cylindrical, curved, 17–30(–50) × 4.5–6.5 mm, slightly corrugated over seeds, dehiscing apically downward. |
Seeds | olive green or brownish, obovoid. |
brownish olive green becoming gray, paddle-shaped to pyriform. |
2n | = 26, 28. |
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Senna occidentalis |
Senna bauhinioides |
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Phenology | Flowering mid summer–early winter. | Flowering mid spring–mid fall. |
Habitat | Disturbed habitats, waste places, roadsides. | Stony hillsides, plains, bajadas, dry washes. |
Elevation | 0–1200 m. (0–3900 ft.) | 100–1800 m. (300–5900 ft.) |
Distribution |
AL; AR; FL; GA; IA; IL; IN; KS; LA; MA; MD; MO; MS; NC; NY; OK; SC; TN; TX; VA; Mexico; Central America; South America; West Indies [Introduced in North America; introduced also in tropical and subtropical Eurasia, Africa, Australia]
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AZ; NM; TX; Mexico (Chihuahua, Coahuila, Nuevo León, Sonora)
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Discussion | Although Senna occidentalis is probably native to the tropical New World, the species is now weedy in so many countries worldwide, including also other parts of the New World, that the exact range of its geographic distribution as a native is a matter of speculation (H. S. Irwin and R. C. Barneby 1982). In the flora area, it is considered as naturalized (R. Kral et al. 2012; R. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Senna bauhinioides is one of three sennas in North America that can form and sprout from a woody taproot (along with S. pumilio and S. ripleyana; H. S. Irwin and R. C. Barneby 1982). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | Fabaceae > subfam. Caesalpinioideae (excluding Mimosoid clade) > Senna | Fabaceae > subfam. Caesalpinioideae (excluding Mimosoid clade) > Senna |
Sibling taxa | ||
Synonyms | Cassia occidentalis, Ditremexa occidentalis | Cassia bauhinioides, Earleocassia bauhinioides |
Name authority | (Linnaeus) Link: Handbuch 2: 140. (1829) | (A. Gray) H. S. Irwin & Barneby: Phytologia 44: 499. (1979) |
Web links |