Desmodium barbatum (L.) Benth.

Gloabl description

Desmodium barbatum is a species of variable form and behaviour, prostrate, ascending or erect, short-lived perennial or annual. The stem is covered with dense white or tan hair. The stipules are narrow and pointed. The leaves are alternate, compound with 3 leaflets, elliptic, oval or obovate, mucronate at the apex, with a sparsely pubescent upper surface and a densely pubescent lower surface. The inflorescence consists of dense terminal racemes, characterised by flowers with a calyx covered with long dense yellow hairs. The corolla, typical of legumes, is red, pink or white. The characteristic fruit of the Desmodium genus is a hairy pod with clearly marked dehiscent articles, indented between the articles at the level of the ventral vein.

Cotyledons

The cotyledons are short-stalked, with an oval or subreniform, slightly fleshy, glabrous, light green blade.

First leaves

The first leaves are alternate, simple, petiolate with a kidney-shaped blade with a slightly cordate base and emarginated apex. The following leaves become compound, trifoliolate. The leaflets have an oval blade with a subcordate base and emarginate apex, with visible veins, dark green on the underside. Tufts of hairs are present at the base of the petioles.

General habit

Desmodium babartum is variable in form, ranging from a prostrate plant on the ground to an ascending or erect plant depending on the environment and the surrounding plant cover. It is 20-60 cm long.

Underground system

The main root is taproot.

Stem

The stem is cylindrical, solid, 1.5 to 3 mm in diameter, branching from the base. It is covered with more or less dense, white or tawny yellow hairs.

Leaf

The leaves are alternate, compound, trifoliolate. At the base of the petiole is a pair of free persistent stipules, narrowly triangular in shape, with an asymmetrical base, inserted obliquely to the base of the petiole, and an acuminate apex, 6 to 12 mm long. They are pubescent and ciliated. The petiole is 8 to 15 mm long and the rachis 3 to 5 mm long. The petioles of the leaflets are 1 to 3 mm long. They are pubescent. At the base of the petioles, the 0.5 to 5 mm stipels are persistent, linear, acuminate and pubescent. The leaflets are elliptic, slightly oval or slightly obovate, with a rounded base, a rounded mucronate apex, and an entire margin. The terminal leaflet is slightly larger than the lateral leaflets. It is 14-45 mm long and 8-18 mm wide. The upper surface is lightly pubescent with white applied hairs, the lower surface is densely pubescent with white applied hairs. The veins are pinnate, arching towards the margin and clearly prominent on the underside.

Inflorescence

The inflorescence consists mainly of compact, 1.5-5 cm long, multiflorous terminal racemes.

Flower

The flowers are borne on geminate pedicels, 7 to 7.5 mm long, pubescent, with a 6 to 6.5 mm long lanceolate oval bract at the base, abundantly ciliated with tan hairs. The calyx is long silky, hairy, ciliated and deeply lobed. The lower lobe is formed of 3 equivalent teeth of 4 to 5 mm, the upper lobe is formed of 2 attenuated oval teeth. Corolla typical of legumes, red, pink, purple to white. The standard is broadly obovate, sometimes unguiculate, 5 mm long and 3 to 5 mm wide. The wings are obtuse oblong, 4 to 5 mm long and 2 mm wide. The keel is truncated at the tip, 4 mm long.

Fruit

The fruit is a hairy pod with 2-5 dehiscent articles, 6-12 mm long and ending in a point. It is straight along the dorsal vein and well indented between each article along the ventral vein. The articles are quadrangular, 2-3 mm wide and finely pubescent.

Seeds

The seeds are subelliptic to subreniform, compressed, with a thickened margin. They are 2 to 2.3 mm long and 1.4 to 1.5 mm wide and dark brown in colour.

Origin

Desmodium barbatum is native to tropical America and tropical Africa, until Madagascar.

https://www.gbif.org/species/10812682