Gomphocarpus physocarpus (Balloon Milkweed)

Native to southern Mozambique, Eswatini and South Africa, this upright shrub has slender branches and narrow, opposite leaves. Hanging clusters of white flowers have strongly reflexed petals and a central crown tinged with pink or purple. Large, inflated, nearly spherical fruits bear numerous soft, hairlike projections. When ripe, they split open to release seeds with silky tufts that aid wind dispersal. Broken stems and leaves exude milky latex. The plant grows in seasonally wet grassland and disturbed ground and has naturalized in eastern and southern Australia. Its leaves feed African monarch butterfly caterpillars, but the plant is poisonous to people and livestock if eaten. Photographed in Colombia.