Well, folks, it’s late summer, and that means it’s time for a couple more botany terms! Are you ready? OK!
The truly vibrant flowers in this photo deserve a thought or two. Of course, it is the corolla which is vibrantly colored, the corolla consisting of all the petals fused at their edges (5 petals in this case). Below or “behind” the corolla is going to be a green calyx, which consists of all the sepals fused together (5 sepals in this case). Now, when flower parts of like structure are fused to each other, we say that they are “connate”. So here, the corolla is made up of 5 connate petals, and the calyx is made up of 5 connate sepals. If you look inside the corolla, you will see 5 stamens…you know, the little stalked things that produce the pollen. Each of the 5 stamens here is fused to the inner surface of the corolla. We say then, that the stamens are “adnate” to the corolla, since stamens and the corolla are not “like” parts. (You can remember it this way: “adnate” refers to unlike things stuck together, like your finger “ad”hered to a bandaid.)
Then there is that very vibrant corolla with the petals almost totally fused, but free at their tips, forming lobes. A corolla with its petals connate and with perfectly equally shaped and sized (and colored) lobes is what we call “radial” or star-shaped. When the corolla with its connate petals is irregularly shaped, with a right “side” and an equal “left” side, like a sage flower, or touch-me-not, the term to use is “bilateral”. So, what about our Mystery Plant? At first glance, the corolla is radial, but if you look closely, you’ll see that the upper 3 corolla lobes are together about equal to the lowest two. And, the lowest part of the corolla has a bright yellow streak on it. We might say that the corolla here is radial, but weakly bilateral. OK, enough terms already.
Our Mystery Plant is a cultivar of one of about 45 wild species (probably hybridized) of a South American genus, and is a very near relative of our beloved petunia. Both are members of the tomato family, which of course gives us tomatoes, potatoes, angel-trumpet, tobacco, peppers (that is, chili peppers and green peppers, not black pepper, which is totally different), and everything in this family features a corolla of 5 connate petals. Many of the species in this family, but certainly not all, feature quite an array of special compounds called alkaloids, which often have profound physiological effects on animals, both vertebrate and invertebrate. Think capsaicin, which provides the hot (and wonderful!) taste of many peppers, and nicotine, which of course comes from tobacco. You may recall that angel-trumpet, although bearing attractive flower, is highly toxic.)
You can find our Mystery Plant at just about any big-box gardening shop, often overflowing the margins of a hanging basket. They also do well in window boxes, or even as bedding plants. Make your hummingbirds happy.
[Answer: “Million bells,” Calibrachoa cultivar]
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John Nelson is the retired curator of the A. C. Moore Herbarium at the University of South Carolina in Columbia SC. As a public service, the Herbarium offers free plant identifications. For more information, visit www.herbarium.org or email email@example.com.