It grows as an erect, spreading or scrambling shrubby herb, up to 1.5 metres tall, usually with a great many stems. Its leaves are dark green, stiff, with sharp spines at the end of each deep lobe: very much like those of holly (Ilex). Flowers are blue, purple or white, and occur in spikes terminal on the branches. The fruit is a square-shaped capsule, which explodes when ripe, projecting the seeds up to two metres from the plant. Seeds are off-white, and flat.
Distribution and habitat
It occurs in the undergrowth of mangroves in south-east Asia, including northern Australia.