Senna occidentalis |
Senna pilosior |
|
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coffee senna, septicweed |
trans-Pecos senna |
|
Habit | Herbs, perennial, bushy, to 2.2 m; branches dark green and blackish. | Herbs, perennial, to 0.7 m. Leaves slightly sclerophyllous, 1.5–7.5 cm, hairy; stipules tardily deciduous; extrafloral nectary 1, between leaflet pair, stipitate; leaflet pairs 1, blades broadly, obliquely obovate to oblong-obovate, 15–40 × 10–25 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. |
|
Racemes | usually (1 or)2–5-flowered; bracts caducous, longer than bud, often blackish green. |
2–6-flowered; bracts caducous. |
Pedicels | 8–21 mm. |
6–15 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 persistent into developing fruit, pale green; corolla yellow, longest petal 8.5–10 mm; androecium not heterantherous, stamens 7, staminodes 3; anthers 2.3–3.7 mm, dehiscing by 1 apical pore, apical appendage 0; gynoecium nearly linear, ovules 16–26; ovary densely hairy; style linear. |
Legumes | ascending, flat, slightly curved or straight, linear, 80–135 × 6.5–9.5 mm, corrugated over seeds, dehiscent. |
erect, flat, straight, 20–40 × 5.5–7.5 mm, corrugated over seeds, dehiscing apically downward, with 1 series of seeds. |
Seeds | olive green or brownish, obovoid. |
dull pinkish or grayish brown, pyriform. |
2n | = 26, 28. |
= 28. |
Senna occidentalis |
Senna pilosior |
|
Phenology | Flowering mid summer–early winter. | Flowering spring–mid fall. |
Habitat | Disturbed habitats, waste places, roadsides. | Sandy banks, desert washes. |
Elevation | 0–1200 m. (0–3900 ft.) | 600–1500 m. (2000–4900 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]
|
TX; Mexico (Chihuahua, Coahuila, Durango) |
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 pilosior is the only senna in North America with sepals persisting into fruit development and falling off before fruit matures and dehisces. Persistent sepals are diagnostic to distinguish S. pilosior from the close relatives S. bauhinioides and S. durangensis; the trio is, in fact, characterized by a history of repeated misidentifications (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 var. pilosior, C. pilosior |
Name authority | (Linnaeus) Link: Handbuch 2: 140. (1829) | (B. L. Robinson ex J. F. Macbride) H. S. Irwin & Barneby: Phytologia 44: 500. (1979) |
Web links |