Common Milkweed

Milkweed furnish venom for Monarch butterflies. The leaves are poisonous to most animals, but Monarch butterflies eat nothing else. As a result, they and the butterflies they become are toxic to predators. Also of interest is the crownlike flowers of milkweed are cunning traps for insect pollinators. Each blossom has five nectar cups with smooth, incurved horns growing from them. When an insect lands, its foot slips on a horn and goes into the slit between the two cups. If the insect is not strong enough to pull its leg out, it dies there. At the next flower, its foot slips again; this time, as it picks up more pollinia, it deposits the first two beside the cups, where the pollen develops to fertilize future seeds.