Crotalaria pallida var. obovata.
Crotalaria obovata and Crotalaria pallida are synonyms.
The Smooth or Streaked rattlepod is widely naturalised along the S.E. Queensland coast.
An annual herb up to 2 m high with longitudinal ridges down the stems.
Short hairs that lie flat along the stem point up towards the tip.
Alternately arranged leaves are on a petiole up to 5 or 6 cm long.
There are usually no stipules but sometimes 3 mm ones that fall off early.
Leaves are trifoliate with 3 leaflets on short petiolules.
The petiole, midrib and petiolules have hairs like those on the stem.
Leaflets are elliptic to obovate with a rounded tip that may be notched.
The terminal leaflet is almost always over 3 cm long and up to 8 or 9 cm.
Leaflets are up to 4.5 cm wide.
There are hairs on the lower surface of young leaflets but less or none on older leaves.
Terminal inflorescences are a raceme up to 30 cm long with up to 40 flowers along the midrib.
Flowers, on a pedicel around 4 mm long are up to 15 mm long.
The bases of the 5 sepals are fused into a tube 2 to 3 mm long with pointed lobes 5 to 6 mm long.
The outer surface has hairs that lie flat along the surface.
The 5 petals form a typical pea-shaped flower.
The erect upper standard petal is the largest.
The 2 side wing petals, shorter than the keel, have a narrow claw base.
The lower 2 keel petals, partly fused along their lower side fold up forming the sharp keel.
Petals are yellow with purplish or reddish-brown veins.
The veins are more prominent on the standard petals.
There are 10 stamens with their filament bases fused into a tube that is open on the upper side.
Anthers alternate between long basifixed and short dorsifixed ones.
The superior ovary has 1 locule with numerous ovules in a row down one side.
The single style has hairs on one side towards the tip.
There may be hairs on the ovary.
The fruit are pods up to 4.5 cm long that may have a few hairs.
The beak on the end, from the style is around 1 cm long.
Mature pale brown pods can have over 50 kidney-shaped seeds.
The smooth seeds, around 3 mm long are mottled in brown, yellow and grey-green.