Euphorbia stellata aka Milkthorn

Euphorbia stellata is a small succulent, a plant that stores water. It belongs to the spurge family, Euphorbiaceae. It comes from South Africa's south and south-central Cape region. Records place it in the Eastern Cape at Port Elizabeth, Albany and Peddie. Its home has dry shrubland and desert climates. It grows among grass and pebbles, often in full sun. Its thick tuber holds it in cracks between rocks.

A woody base, called a caudex, stores water below ground. A short stem joins a thick root shaped like a turnip. The caudex stands about 0.16–0.49 feet [0.05–0.15 metres] tall. It reaches about 0.20–0.23 feet [0.06–0.07 metres] wide, sometimes more. These sizes refer to the caudex, not the whole plant. Growers often raise this swollen base above the soil for show. The water it stores helps the plant cope with drought.

Flat branches spread from the top of the caudex. They hug the ground and reach about 0.49 feet [0.15 metres] long. Each has two ribs. The skin is dark green with pale marks like feathers. Wavy teeth and pairs of spines line the winged edges. These low, spreading shoots give it a medusoid form. The flowers are greenish-yellow and grow in groups called cymes. Small cyathia hold nectar glands. These glands look yellowish and almost meet. The fruit has deep lobes and holds small, egg-shaped seeds.

This plant grows slowly and needs warmth and sun to grow well. It takes full sun or light shade. It can cope with moderate shade too. Give shade-grown plants stronger light in stages to avoid scorch. Use a loose potting mix made mainly of minerals. Choose pots that let water drain well. Water while the plant grows, but never leave its roots standing wet. Keep the mix almost dry in winter. Too much water can cause rot, above all during rest. Feed in summer to help growth. Use a succulent fertiliser rich in potassium.

Growers prize this succulent for show, with its caudex in view. Raise new plants from seeds or branch cuttings. Plants grown from seed can have a more even caudex than cuttings. Let cut wounds dry before planting. Fresh cuts can rot. One account reports survival at about 21°F [−6°C]. That account still says to grow it without frost, in USDA zones 9–12. Warmth helps the plant keep its good looks.