Sesbania pachycarpa DC.

Global description

Sesbania pachycarpa is a tall, upright plant that grows up to 2 to 4 m tall. It has alternate paripinnate leaves with many leaflets. The underside of the rachis is marked by a line of small conical asperities. The flowers are assembled in small axillary clusters. The fruit is a long pod with an acute beak and up to 30 oblong dark brown seeds.

Cotyledons

The cotyledons are oblong to slightly reniform. They are borne by a short petiole of 1 mm. The blade is 12 to 15 mm long and 3 to 4 mm wide.

First leaves

The first leaf is simple. It is carried by a short cylindrical petiole, framed at the base by two linear stipules, 2 mm long and rapidly caducous. The blade is elongate elliptical, 2 cm long and 4 to 5 mm wide. The margin is entire and the top is sometimes mucronate. The faces are glabrous. The central vein is white, clearly visible. The following leaves are compound and alternate. They are paripinnate with 7 to 15 pairs of opposite leaflets. The end of the rachis exceeds the last pair of leaflets by 1 to 2 mm.

General habit

Sesbania pachycarpa is erect. The plant can measure 2 to 4.5 m in height. It is branched at the base in long oblique branches. Towards the top, the branches become shorter and are erect. The base of the stem is subwoody.

Underground system

The root is a taproot.

Stem

The stem is cylindrical and solid. It is glabrous and finely streaked longitudinally or sometimes slightly fluted. The interior is formed of a white pith. The section reaches 2 to 3 cm in diameter.

Leaf

The leaves are compound and alternate. They are paripinnate, up to 60 pairs of leaflets and up to 45 cm long. The petiole is 2 cm long, it is framed at the base by two linear stipules 6 to 9 mm long and provided with some fine hairs on the margin. The underside of the rachis is marked by small conical asperities arranged in line. The leaflets are borne by very short petiolules. The blade is oblong to elliptical. It is 6 to 15 mm long and 2 to 3 mm wide. The longest leaflets are located in the middle part of the leaf. The margin is entire, the base is rounded, very slightly asymmetrical. The summit is rounded and mucronate. The faces are glabrous with only a few fine hairs along the veins and margin. The leaflets are opposite along the rachis or slightly offset to the point of appearing alternate. The apex of the rachis, extending 1 to 2 mm beyond the insertion point of the last pair of leaflets.

Inflorescence

The flowers are assembled in small clusters of 3 to 6, in the axils of the leaves.

Flower

The calyx is cup shaped, 5 mm long and terminated by 5 short triangular teeth. The corolla is 25 mm long. The upper petal (standard) is rounded at the top. It bears at the base, 2 appendages elongated at the rounded end, not terminated by a free appendice. It is yellow, punctuated and streaked with purple-brown on the outer surface. The lateral petals (wings) are elongated, bearing at the base of the outer face 2 fins. They are yellow in color. The lower petal (keel) carries 2 curved teeth in the middle part. It is greenish, finely streaked with purple-brown. Filets of 9 stamens are welded into a gutter applied to the ovary. The tenth stamen, in the dorsal position, is free.

Fruit

The fruits are straight or slightly curved pods that can be 15 to 25 cm long and 3 to 4 mm wide. The margin of the pod is marked by restrictions in the partitions between the boxes. The summit forms an acute beak. Pods may contain more than 30 seeds.

Seed

The seeds are oblong, 4-5 mm long and 2 mm wide. They are dark brown with some gray mottling.

Origin

Sesbania pachycarpa is native to Africa

Worldwide distribution

This species is present in Africa from Mauritania, the Cape Verde Islands, to Namibia in the south and Eritrea in the east.

https://www.gbif.org/species/2970716