Mystery Plant! #730
By John Nelson
One of my pet peeves as a plant taxonomist comes up again when we look at this little plant. Its common name suggests that it is a grass—but it is not a grass. Not even close.
Nevertheless, it looks at little bit like grass, with elongated, slender grass-like leaves, and a long stalk. Each stalk makes a seed-pod looking thing, which might resemble a grass, but the individual flowers, of course, aren’t grass-like at all.
A tuft of slender basal leaves is present, and in the summer, each plant will produce one to several elongated, leafless stalks. The flowers of this herb are small, quite small in fact, but rather conspicuous when open. Several flowers are compacted into a tight cone-like head, and one of these heads will terminate each of the flowering stalks produced. Each flower is subtended by a fairly hard, fingernail-shaped bract, which is chestnut-colored. The flowers themselves are perfect (male and female parts present in each individual flower), featuring three curious sepals (the two side sepals are shaped like little boats, while the middle one is a minute little wisp) and three bright yellow petals, squeezed out of the flower from the edges of the bract. The petals are quite delicate, like the thinnest tissue, and last only a few hours before shriveling into gooey nothingness. Bees or other insects sometimes visit the flowers, but as no nectar is produced in them as a reward, not many insects seem very interested. Wind-pollination is most likely to be the rule with these flowers. There are a few stamens, along with a single ovary. The ovary ends up forming an elliptical, tan capsule, eventually splitting apart, releasing very, very tiny seeds. Because the diagnostic features of this plant (and its relatives) involve such small parts, separating them is not always easy, and sure enough, these native American species are thought, generally, to be one of the more difficult groups to work with, as far as telling them apart. To compound the identification issues, a given species may exhibit considerable size differences depending on its habitat, which often increases its variability.
It’s interesting that this little plant has about 20 or so near relatives elsewhere in the eastern half of the United States; several species are rare. Most of them are found toward the Atlantic or Gulf Coasts. Our Mystery Plant occurs on the coastal plain from South Carolina throughout much of Florida, and west near the Gulf to Alabama. (It’s also present in Central America and the West Indies.) It likes damp places, most often in ditches or on floating mats, or in Carolina bays. Several of its relatives, though, like dry, sandy places.
These various species are important indicators of healthy natural ecosystems. They don’t seem to provide much of a food source for critters, and they don’t have much of a “use” for humans. And that’s OK: they are a natural part of our landscape, and hopefully always will be around..
[Answer: “Yellow-eyed grass,” Xyris elliottii]
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 email@example.com.
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