Five-leaf cassia

Chamaecrista mimosoides, the feather-leaved cassia or fishbone cassia, is an annual or short-lived perennial herb to small subshrub in the Fabaceae with a pantropical and subtropical distribution, native to grasslands, open woodland, roadsides and disturbed ground across Africa, southern Asia, northern Australia and the Americas. Plants are erect to spreading, 20 to 100 centimetres tall, with slender ridged stems that are sparsely to densely covered with short curved hairs. The alternate, sensitive leaves are pinnately compound with 20 to 70 pairs of very small, narrowly oblong leaflets 3 to 7 millimetres long, the petiole bearing a small sessile or short-stalked gland between or below the lowest pair of pinnae — a key feature distinguishing the genus from Senna. Bright yellow flowers about 8 to 15 millimetres across, with five slightly unequal petals, are borne singly or in clusters of two to four in the upper leaf axils. The fruit is a narrowly oblong flat pod 2 to 5 centimetres long, dark brown when ripe, splitting elastically and twisting to fling out a row of 10 to 20 flat angular seeds.