Crotalaria verrucosa L.

Linnaeus, C. von (1753) Species Plantarum 2: 715. Type: Habitat in India.

Blueflower Rattlepod; Rattlepod, Blueflower

Usually flowers and fruits as a shrub about 1-1.5 m tall but also flowers when smaller.

Twigs 3 or 4 winged. Stipules foliaceous, falcate, about 12-38 x 13-31 mm, apex acuminate. Leaf blades about 6.5-15 x 3.5-5.5 cm, petioles about 0.4-1 cm long, upper and lower surfaces clothed in short white hairs. Lateral veins about 7-13 on each side of the midrib.

Flowers subtended by narrow lanceolate, about 9 mm long, bracts, apex inflated and hooked. Flowers about 16-18 x 23 mm. Calyx tube about 3-4 mm long, lobes about 6 mm long. Stamens ten, filaments fused into a tube about 6-7 mm long, open on one side. Petals: standard about 16 x 12 mm, wings about 12-15 mm long, keel about 12-15 mm long. Stamens dimorphic, the longer filaments with small anthers about 0.8 x 0.8 mm and the shorter filaments with longer anthers about 4 x 1 mm. Ovary densely clothed in white hairs. Style about 8-9 mm, hairy towards the apex.

Pods cylindrical, about 50-80 x 10-16 mm, hairy, grooved on one side. Seeds about 28-32 per fruit. Outer surface of the seeds and the inner surface of the pod oily. Radicle adjacent to the cotyledons.

Cotyledons oblong, about 19-25 x 9-12 mm. Cotyledon petioles flattened on the upper surface with a purple rib on each side which runs down the hypocotyl to form a 'V'. Stem, petioles and hypocotyl hairy. At the tenth leaf stage: leaf blade +/- ovate or rhomboid, apex acute or obtuse. Upper and lower surface of the leaf blade clothed in pale +/- prostrate hairs. Stipules comparatively large, about 5-10 x 4 mm, +/- foliaceous and photosynthetically active. Seed germination time 6 to 8 days.

Occurs in WA, NT, NEQ, CEQ and southwards almost to south-eastern Queensland. Altitudinal range in northern Australia from near sea level to 750 m. Grows in open forest, riparian vegetation, vine thickets and on agricultural land. Also occurs in Asia and Malesia.

This plant is poisonous.

This species is of no grazing significance; not toxic to rats in laboratory tests. In the Caribbean it has been found to be salt-tolerant. Hacker (1990).