The Original Mystery Plant
Dr. John Nelson

Photo by Linda Lee

The Mystery Plant belongs to the mint family, which in botanical- ese is called the Labiatae, or, just as proper, the Lamiaceae.

The first of these family names is by far the older, known from antiquity. The word Labiatae refers to the presence of a flower with lips, as in an upper lip and a lower lip. Practically everything in the mint family has a flower whose corolla is indeed bilabiate and features an upper and a lower lip.

Commonly, the upper lip protects the stamens and pistils within while the lower lip provides a convenient landing platform for busy bees.

The more recent name, Lamiaceae, is derived from the modern legalistic protocol of naming a family after what is called the type genus. In this case, the type genus for the mint family is Lamium. The modern name for the family is Lamiaceae. The older name is Labiatae. Both names are synonymous and equally valid amongst botanists.

All the members of the mint family, whichever scientific name is used, are not the mint that goes in iced- tea. Mint is the common name for plenty of species all placed in the genus Mentha, and an aromatic group of species it is.

Lavender, basil, beefsteak plant, sage, horehound, and rosemary, all members of the mint family, have wonderful smells. But there are plenty of species in the family that don't smell good.

The Mystery Plant is not mint, although it is in the mint family. It's an herb that's widely scattered over nearly all of the U.S. and southern Canada, and while it looks something like mint, it has no minty aroma at all.

It's extremely variable in terms of leaf margin toothiness and stem pubescence, and because of this variability, various botanists have proposed a number of subspecies or varietal names to accommodate this confusing variability.

Most botanists tend to dismiss this and think of the species as a single, variable group with one name.

The Mystery Plant likes to grow in rather damp places in woods and thickets often along creek banks. Thin rhizomes are produced below ground, which makes this plant easy to spread around, sometimes to the point of weediness.

The calyx is green and tubular with five teeth. The corolla is attractive and white, or bright pink, and rather unusual for a member of the family. While the corollas of most members of the mint family have an obvious upper lip, The Mystery Plant's upper lip is split down the middle, and looks like there's no lip at all. It's the only member of the family that does this. Answer to this week's mystery plant canadense] [Answer: "American Germander," "Wood-mint," Teucrium

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