White clover is a weed that grows the world over -- there’s a good chance you have some growing in your yard today. The plant that yard-preeners love to hate was spawned about 20,000 years ago when two European clover species hybridized.

 

The family history of white clover (Trifolium repens) was pinned down years ago, but biologists at Washington University in St. Louis have just uncovered the genetic backstory of white clover’s biggest trick. White clover releases toxic cyanide when its leaf tissues are damaged. This chemical defense, a response called cyanogenesis, helps it to deter insect pests. Research published in New Phytologist shows how white clover developed its anti-herbivory superpower with input from both of its seemingly innocuous parents.