Fennel Foeniculum vulgare
Fennel is a familiar herb and vegetable native to the Mediterranean. When I briefly lived in San Francisco, I was astonished to see huge (6 to 8 feet) wild fennel plants in vacant lots and along roadsides. In fact, fennel is considered invasive in California, and creates monocultures in sensitive habitats such as Santa Cruz Island. Fennel has escaped cultivation and grows wild in more than 30 states and on islands around the world, including New Zealand and Hawaii. Here it is pictured growing on the island of Jersey, its taproot deeply embedded in the cement of a German gun bunker.