The Original Mystery Plant
Dr. John Nelson

Photo by John Nelson

The common name of the mystery plant suggests that it is a grass, but it is not.

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 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 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 are perfect (male and female parts present in each individual flower), which feature 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 delicate, thin tissue and last only a few hours before shriveling into gooey nothingness. Bees or other insects sometimes visit the flowers, but no nectar is produced.

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 tiny seeds.

The diagnostic features of this plant and its relatives involve small parts so separating them is not always easy. These native American species are thought 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.

The mystery plant has about 20 or so near relatives elsewhere in the eastern half of the United States; most species are found toward the Atlantic or Gulf Coasts. It 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.

This species, along with its relatives, are important indicators of wetland ecosystems. They don't seem to have much of a use for humans. They are beautiful wildflowers, pretty to look at, and some people like to take the dried stalks home and put them in arrangements. But they are not grass.

Answer to this week's mystery plant [Answer: "Yellow-eyed grass," Xyris elliottii]

Dr. John Nelson is the curator of the USC Herbarium. To learn more about the Herbarium, call 777-8196. The

department also offers free plant identification.

www.herbarium.org