[2] Isotoma axillaris is an upright perennial herb growing to 50 cm high with ascending stems that are often a purplish colour and covered with short, soft hairs quickly becoming smooth.

The leaves are about 1.5–15 cm (0.59–5.91 in) long and 0.5–5 mm (0.020–0.197 in) wide with deep, toothed, linear lobes sharply pointed at the apex.

The lobes are elliptic to oblong shaped, 8–18 mm (0.31–0.71 in) long, but are not joined and form a star-shaped flower.

[4][5] Isotoma axillaris was first formally described by botanist John Lindley in 1826 in Edward's Botanical Register.

[4] Showy isotoma occurs in Queensland, New South Wales and Victoria, often in moist crevices on rocky outcrops.