Genetic differences in clover make one type toxic

That clover necklace you make for your child could well be a ring of poison. That’s because some clovers have evolved genes that help the plant produce cyanide – to protect itself against little herbivores, such as snails, slugs and voles, that eat clover. Other clover plants that do not make cyanide are found in climates with colder temperatures. So, in picking your poison, er, clover, ecology and geography play important roles.