Aeschynomene americana L.

Global description
 
Aeschynomene americana is an annual or shortly perennial plant, spreading to upright, bushy growth habit, sometimes sub lignified at the base, 30 cm to 1.8 m high. The branches are equipped with fine tuberculate hairs. The leaves are alternate narrow and composed of 8 to 40 pairs of linear-oblong leaflets, 2 to 10 mm long, sensitive to the touch. The leaflets are glabrous or ciliated at the margins, 2-4 veined from the base. The inflorescence consists of axillary racemes, 1.5 to 3 cm long, opposite to the leaves or terminals, in zigzag with 1-5 flowers. Papilionaceous flowers are usually pink, with a whitish yellow part often streaked with red or purple at the base of the standard. Fruit are linear to curved pods, transversely articulated, 15 to 30 mm long, having 8 to 12 articles.
 
Cotyledons
 
The cotyledons are kidney-shaped, sub sessile, semi-fleshy without conspicuous venation. The blade is 5 to 8 mm long and 4 to 5 mm wide. It is light green, glabrous.
 
First leaves
 
The first leaves are alternate, paripinnately compound, carried by a petiole, 2 to 3 mm. The leaves consist of 6 to 8 pairs of narrow oblong leaflets. The leaflets are 8 to 12 mm long.
 
Harbor
 
Annual to shortly perennial herb, bushy growth habit, up to 1.8 m high.
 
Underground system
 
The plant has a taproot system.
 
Stem
 
The stem is prostrate to erect, sub lignified at the base, with tuberculate hairs.
 
Leaf
 
The leaves are alternate, compound, paripinnate bearing 8 to 40 pairs of opposite leaflets sometimes becoming alternate; leaflets narrowly oblong, 2 to 10 mm long and 0.5 to 1.8 mm wide, becoming smaller at the tip of the leaf, pointed and mucronate at the end, glabrous or with ciliated margins, with 2 to 5 prominent veins from base to the apex, very visible on the underside. Narrow stipules of 5 to 10 mm long, tapered at the end, striated, sub-peltate, with a tapered lobe of 1.5 to 5 mm long spreading below the attachment point.
 
Inflorescence
 
The inflorescences are axillary racemes, 1.5 to 3 cm long, in zigzag, with 1-5 well-spaced flowers; ovate bracts, 3 to 5 mm long, encircling the axis at the base, striated, margin ciliated with long tuberculate hairs; bracteoles narrow, ribbed, with ciliated margins with bulbous based hairs.
 
Flower
 
Flowers papilionaceous, 5 to 6 mm long, usually pink in colour, with a whitish yellow part often streaked with red or purple at the base of the standard. The calyx is 3.5 mm long, with long scattered hairs, deeply divided into two lobes, the upper bidentate at the top, the lower with 3 short apical tines, the keel is non fibrous.
 
Fruit
 
The fruits are pods, 15 to 30 mm long, including a stipe of 2 to 3 mm long, with 4-10 or more articles; the bottom margin is deeply scalloped between the articles; each article measure 3.5 to 4.5 mm by 2.5 to 3.5 mm, central portion is thick and verrucous, glabrous or with scattered marginal bristles.
 
Seed
 
The seeds are oblique-reniform, 2 to 3 mm long and 1.5 to 2 mm wide, brown.

Origin
 
Aeschynomene americana is native to Central America, Southern USA
 
Worldwide distribution
 
Tropical and subtropical America, often introduced and naturalized in Africa, Sri Lanka, the South West Indian Ocean Islands, tropical Asia, Indonesia, the Philippines, New Guinea and Australia.

https://www.gbif.org/species/2949235