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Argentine senna

Roemer senna, twoleaf senna, twoleaf wild sensitive plant

Habit Shrubs or trees, to 3.5 m. Leaves mesophyllous, 5.5–9.5 cm, glabrous or glabrate; stipules caducous; extrafloral nectary 1, between first leaflet pair, sessile or short-stipitate; leaflet pairs 3, blades oblong-lanceolate, 25–60 × 5–14 mm. 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.
Racemes

4–18-flowered;

bracts caducous.

1–5-flowered;

bracts caducous.

Pedicels

13–23 mm.

9–16 mm.

Flowers

monosymmetric;

calyx brownish to greenish yellow;

corolla golden yellow, longest petal 8–16 mm;

androecium heterantherous, stamens 7, middle stamens 1/2 as long as abaxial or smaller, staminodes 3;

anthers of middle stamens to 3.6–4.8 mm, of abaxial stamens 5.2–6.5 mm, dehiscing by nearly U-shaped pore, apical appendage inconspicuous;

gynoecium incurved, ovules 34–50;

ovary 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

somewhat pendulous, cylindrical, straight, 40–120 × 6–10 mm, corrugated over seeds, indehiscent.

erect, subcylindrical, straight or slightly curved, 20–35 × 4.5–6.5 mm, corrugated over seeds, dehiscing apically downward.

Seeds

dull brown or dark reddish brown, obliquely obovoid or oblong-ellipsoid.

brown or pinkish brown, paddle-shaped or pyriform.

2n

= 28.

= 28.

Senna corymbosa

Senna roemeriana

Phenology Flowering early winter–mid spring. Flowering spring–early fall.
Habitat Thickets, brushy stream and river banks, waste places. Mesquite grasslands, chaparral, draws in shortgrass prairies, barren hillsides, desert washes, roadsides.
Elevation 0–500 m. (0–1600 ft.) 100–2000 m. (300–6600 ft.)
Distribution
from FNA
FL; GA; LA; MS; SC; TX; s South America
[BONAP county map]
from FNA
NM; OK; TX; Mexico (Chihuahua, Coahuila, Nuevo León)
[WildflowerSearch map]
[BONAP county map]
Discussion

Senna corymbosa has been cultivated for over two centuries and is a common ornamental in many botanical gardens worldwide; it has become naturalized in warmer western Europe and South Africa (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
S. alata, S. armata, S. artemisioides, S. atomaria, S. bauhinioides, S. covesii, S. durangensis, S. hebecarpa, S. hirsuta, S. ligustrina, S. lindheimeriana, S. marilandica, S. mexicana, S. multiglandulosa, S. obtusifolia, S. occidentalis, S. orcuttii, S. pendula, S. pilosior, S. pumilio, S. ripleyana, S. roemeriana, S. surattensis, S. wislizeni
S. alata, S. armata, S. artemisioides, S. atomaria, S. bauhinioides, S. corymbosa, S. covesii, S. durangensis, S. hebecarpa, S. hirsuta, S. ligustrina, S. lindheimeriana, S. marilandica, S. mexicana, S. multiglandulosa, S. obtusifolia, S. occidentalis, S. orcuttii, S. pendula, S. pilosior, S. pumilio, S. ripleyana, S. surattensis, S. wislizeni
Synonyms Cassia corymbosa, Adipera corymbosa Cassia roemeriana, Earleocassia roemeriana
Name authority (Lamarck) H. S. Irwin & Barneby: Mem. New York Bot. Gard. 35: 397. (1982) (Scheele) H. S. Irwin & Barneby: Mem. New York Bot. Gard. 35: 282. (1982)
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