This is a weedy species that grows in coastal areas of California. According to research by Norman Ellstrand's group at UC Riverside, this species is evolving in a quantifiable manner. It is a hybrid between Raphanus sativus, the common radish, and Raphanus raphanistrum.Awesome. Bernal Hill has a large population of this wild radish every year. I consider it a scourge, but I will see it with new eyes from now on.
Curiously, the same hybrid occurs elsewhere in similar climates such as that of South Africa, but something special about ecosystems in California has allowed it to proliferate. It is now different enough from either of its parents that Ellstrand's group is considering describing this as a new species. This has occurred within the timespan that the two parents were brought together by humans in California.
There are many color variations of this evolving species. It is exactly through this variation that the process of natural selection works. If allowed to go its own way, some of these color morphs may persist, others may perish, all depending on the selective forces present where they occur. Eventually, each of these, via time and selection, could become a species of its own. California thus would be the center of diversity for a new group of Raphanus species.
See also Nhu's fabulous fungus box.