Senna occidentalis |
Senna roemeriana |
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coffee senna, septicweed |
Roemer senna, twoleaf senna, twoleaf wild sensitive plant |
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Habit | Herbs, perennial, bushy, to 2.2 m; branches dark green and blackish. | Herbs, perennial, to 0.7 m. Leaves slightly sclerophyllous, 2.5–9.5 cm, hairy; stipules caducous; extrafloral nectary 1, between leaflet pair, shortly stipitate; leaflet pairs 1, blades lanceolate-oblong or lanceolate, 20–70 × 4–14 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. |
1–5-flowered; bracts caducous. |
Pedicels | 8–21 mm. |
9–16 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, pale green; corolla yellow or orange-yellow, longest petal 12–17 mm; androecium not heterantherous, stamens 7, staminodes 3; anthers 2.2–3.3 mm, dehiscing by 1 apical pore, apical appendage 0; gynoecium nearly linear, ovules 22–40; ovary densely hairy; style slightly incurved. |
Legumes | ascending, flat, slightly curved or straight, linear, 80–135 × 6.5–9.5 mm, corrugated over seeds, dehiscent. |
erect, subcylindrical, straight or slightly curved, 20–35 × 4.5–6.5 mm, corrugated over seeds, dehiscing apically downward. |
Seeds | olive green or brownish, obovoid. |
brown or pinkish brown, paddle-shaped or pyriform. |
2n | = 26, 28. |
= 28. |
Senna occidentalis |
Senna roemeriana |
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Phenology | Flowering mid summer–early winter. | Flowering spring–early fall. |
Habitat | Disturbed habitats, waste places, roadsides. | Mesquite grasslands, chaparral, draws in shortgrass prairies, barren hillsides, desert washes, roadsides. |
Elevation | 0–1200 m. (0–3900 ft.) | 100–2000 m. (300–6600 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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NM; OK; TX; Mexico (Chihuahua, Coahuila, Nuevo León)
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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.) |
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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 roemeriana, Earleocassia roemeriana |
Name authority | (Linnaeus) Link: Handbuch 2: 140. (1829) | (Scheele) H. S. Irwin & Barneby: Mem. New York Bot. Gard. 35: 282. (1982) |
Web links |