Mystery Plant! #747
By John Nelson
I knew it would happen: it’s gotten cold here in central South Carolina, definitely sweater-weather, at least on these brilliant, clear mornings. I managed to get in one more botany field trip last week just before it got chilly. You might say I struck gold. Here’s a plant that almost shouts out “gold”. And, taking one look at it, you’ll know pretty much right off that this is yet another member of the sunflower family (Asteraceae), different members of which have been featured abundantly in this column. So just for a quick review, a few words about the sunflower family.
The individual flowers of each species in the family are small, and arranged in variously sized heads. (The fancy word for one of these heads is “capitulum”.) The flowers are tightly surrounded by variously shaped bracts, these coming in a variety of textures and colors (mostly greenish though) as well, depending on the species. A ring of flowers occupies the outer edge of the capitulum, each of these flowers with an ovary down at the bottom. The petals of these flowers are fused into a strap-shaped corolla…and botanists like to say that this is a “ray” flower. The central part of the capitulum is home to a different class of flowers, the “disk” flowers, whose corollas are much shorter than the rays, and tubular. The matured ovary of each flower, or fruit, is called an “achene”, and each one contains a single seed. Think unshelled sunflower seeds. (They’re fruits…not seeds.)
What you see in the photograph is a plant within a group of species which most people call “tickseeds”, and that genus is Coreopsis. They are called “tickseeds” because the matured achene produced by each flower resembles a bug, or a tick…although a considerable amount of imagination is needed here. The genus consists of about 40 species, most of which are North American. There are species of them which bloom in the spring, and then those which are late-autumn bloomers. Tickseeds, in general, have the bracts surrounding their capitula in two series: a row of very short ones below, with an upper row of somewhat longer, egg-shaped bracts. Most tickseed species have yellow or gold rays, although a few species’ will be pink or purple. The disk corollas, again depending on the individual species, will be golden, or deep wine-red, almost black. It’s interesting to know that among the tickseed species, the ray flowers are basically sterile, producing no fruits. The ripe, fertile achenes are made by the disk flowers.
Our Mystery Plant is actually a rare one, known from the Coastal Plain of South Carolina and Georgia, and over into the Florida panhandle. That’s it. It seems to prefer soils that are rich in limestone. It has bright green foliage, the leaves with hairy stalks. The plants get to be a couple of feet tall, and they commonly grow in colonies, with many hundreds of individuals. When they start blooming, it is quite a show. But don’t pick them (or any other wildflowers), so everybody can get a look.
[Answer: “Chipola tickseed,” Coreopsis integrifolia]
John Nelson is the retired curator of the Herbarium at the University of South Carolina, in the Department of Biological Sciences. As a public service, the Herbarium offers free plant identifications. For more information, visit www.herbarium.org or email firstname.lastname@example.org.
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