For a recent XKCD, Randall Munroe celebrates the the magical brassica oleracea plant.
Brassica oleracea is a species of plant that, like the apple, has a number of different cultivars. But these cultivars differ widely from each other: cabbage, kale, broccoli, brussels sprouts, kohlrabi, collard greens, and cauliflower.
Welcome, redwood, to the family, er, species.