Cajanus.
Family Fabaceae > Subfamily Faboideae.
Most of the 37 species are native to Africa & Asia.
Australia has 11 species of which 10 are native and 1 is naturalised.
Most are erect perennial shrubs some of which are short-lived.
There are a few herbs and some vines that climb by twining.
The alternately arranged leaves are on a petiole with small stipules at the base.
The 3 leaflets are on short petiolules with tiny stipels at the base.
The elliptic to obovate leaflets are from 2 to 10 cm long.
The leaflet edges are smooth and the tips are pointed.
There are often hairs on the lower surface and sometimes the upper.
Characteristic are the small yellow glands on the lower surface.
Axillary (terminal) inflorescences can have 1 to 15 or 20 flowers.
They are racemes with flowers, on a stalk (pedicel), that open from the bottom up.
There are bracts at the base of the peduncle but no bracteoles on the pedicels.
The calyx has 5 unequal lobes of which the upper 2 may be variously fused.
The corolla, up to 3 cm long is a typical pea-shape.
The largest petal, the upper standard has appendages (auricles) near the base.
There are 2 side wing petals and the 2 curved keel petals are partially fused.
Petals are yellow or orange with red or purplish markings.
There are 10 stamens with the filament bases fused into 2 bundles.
The anthers are dorsifixed.
The ovary has 1 locule with a few seeds.
Fruit are dry oblong pods (legumes) that open along both sutures.
They are constricted between the seeds and have a beak at the tip from the style.
The surface has dense hairs and tiny glands.
The up to 10 round to kidney-shaped seeds can be white, brown, cream, blackish-purple or mottled.
J.F.
