When you look closely at our Mystery Plant, you can rather easily tell that it belongs to the bean family. Each flower is what we call “papilionaceous,” and in a fanciful way, butterfly-shaped. Five petals are present, all a beautiful pink or pale magenta. Four of the petals are about the same shape and size, and occur in two pairs, closely wrapped about the shy stamens and reclusive pistil. The largest of the five petals is what we call a “banner” (as in a flag), since it is the most prominent of the five, and indeed, probably has something to do with attracting pollinators. The banner is pink like the other petals, but also sports a deep purple blotch in the center, sort of like a bulls-eye. We call this blotch an “eyespot.”
This gorgeous herb has over 200 fairly close relatives, all close enough to be placed in the same genus. These various species are mostly found in North America, including the rather familiar Texas bluebonnet, which Texans are proud to have as their state flower. Additionally, some species are native to South America and the Mediterranean. This one is found in open, sandy places of the coastal plain such as roadsides and powerlines, and also shows up in less disturbed forests. It occurs naturally from the eastern end of North Carolina down into the panhandle of Florida, and then over to Louisiana. In all my botanical travels, I’ve never seen great amounts of this plant anywhere, and I suspect that it could be considered rather uncommon within its range.
It grows in clumps, sometimes forming large, spreading patches. The plants are very leafy, and the stems, in full bloom, can be a couple of feet tall, maybe more? The leaves are a bit unusual in being simple, that is, not divided into leaflets, as with most of the members of the genus. The leaves are somewhat sword shaped, up to 7” or so long. The stems and leaves are covered with rather shaggy hairs, and so are the bean pods (legumes) which follow the flowers. Each ripe legume will contain several hardened seeds.
Now those of you who are fans of Harry Potter may remember one of Harry’s friends, a Mr. Remus Lupin, who is something of a werewolf. This brings us to a curious feature of our Mystery Plant, whose generic name directly refers to wolves, as well. The word “lupus” is the Latin word for wolf. For the longest time, it was thought that these plants were bad for the soil on which they grew, ravenously (like wolves) robbing the soil of its nutrients. Yet another old-wives’ tale! This plant, being a member of the bean family, is actually good for the soil. You’ll recall that members of the bean family very commonly have friendly relationships with special bacteria, these living in nodules in the plants’ roots. The happy bacteria are able to produce nitrogenous compounds which end up in the soil. That makes the plants happy.
[Answer: “Lady lupine," Lupinus villosus]
John Nelson is the curator of the A. C. Moore Herbarium at the University of South Carolina, in the Department of Biological Sciences, Columbia SC 29208. As a public service, the Herbarium offers free plant identifications. For more information, visit www.herbarium.org or call 803-777-8196, or email firstname.lastname@example.org.