You may have seen coverage of a recent paper in Nature in which Kew researchers quantified the rate of plant extinction over the last 250 or so years. The headline number is about 3 species have been going extinct per year, which is about 500 times the background rate. But I know that what you really want to know is how many of these are crop wild relatives. Well, my friends at CIAT worked their database magic, and came up with the following list of extinct species which are classified by at least one source as a crop wild relative:
Which means about 1 per decade or thereabouts. But that, clearly, is just a minimum.
Perhaps I’ll try to map where these plants were last seen.