Euphorbia heterophylla (EUPHORBIACEAE) Milkweed

Weeds to Whack

An annual plant with an upright and branching stem native to tropical America. Stems and leaves exude a milky sap when broken. Has a poinsettia-like inflorescences. Main stems are 3-8 mm thick, growing upright to 80 cm. Leaves on petioles (0.5-4 cm) are lobed with a pointed tip, oppositely arranged at the lower nodes, alternate higher up the stem and opposite again near the flowers. Separate male and female flowers are borne in clustered cup-like inflorescences at the tips of the branches. Known as a cyathium, this type of inflorescence is characteristic of the Euphorbiaceae family. Fruits are hairless and green, seeds are egg-shaped brownish or mottled grey in colour. High risk weed in the catchment, spreading rapidly.

Photo: Robert Whyte