Ferns – ferns – wonderful plants. Such an ancient group: they were around a long time before there were any dinosaurs. Their and their relatives' fossilized remains make up significant parts of the coal deposits around the world, and of course a good bit of the carbon in their plant bodies – too much, no doubt – is now floating around in the air, after being burned.

Modern ferns commonly contribute to natural landscapes all over the world; some are tiny and some are enormous ... just think of the tree ferns, especially those of Australia and New Zealand. Many species are valuable for ornamental and garden use, and there are various species which are edible: Try eating some “fiddleheads” if you get the chance.

You will remember from botany class that ferns have interesting life cycles, and they reproduce from spores; no flowers, no seeds. Their spores are produced, not surprisingly, in tiny structures called “sporangia,” but don't worry, we won't go into all the gory details. Now, in most ferns, these sporangia are grouped together in tiny, tiny patches on the back side of the leaf. Each one of the patches is called a “sorus.” The plural of the word “sorus” is “sori,” and there can be plenty of sori scattered in various ways on the leaf surface. The pattern of their distribution and the presence of associated structures is important in the business of separating the many thousands of different species of ferns from each other.

Why, the other day, during my class field trip, I was explaining all this to my students. We were looking at a fern whose sori were orange and easily seen on the leaves. I shared with my students an imaginary scenario in which a tiny toad was crouching below one of the ferns. As the spores fell from the fern's sporangia, the indignant amphibian looked up to the fern, and said, “Hey! Watch where you're dropping your spores!” The embarrassed fern, of course, said, “Sori about that!” (My students love such stories, but some of them think my humor is infernal.)

Anyway, this Mystery Plant is a fern native of eastern Asia, and now quite popular here in the U.S. as a cultivated plant. Its fronds are bright green and a bit leathery, and sure enough, it will produce plenty of sori on the lower frond surface. The fronds are divided into a number of sharply pointed divisions, or “pinnae,” which somewhat resemble the leaves of a holly tree.

This fern will form a rounded mound of evergreen foliage, each frond featuring a long stalk with plenty of orange-brown scales. The plants grow well in pots, and they can handle both sunny and shady situations. This species has been recorded as an introduction in the warmer parts of the U.S., apparently as escapees from cultivation. Thus, you might see it growing from cracks in the masonry in Tallahassee, Fla., Savannah, Ga., or Charleston, and I've even seen it growing “wild” here in Columbia.

John Nelson is the curator of the A.C. Moore Herbarium at the University of South Carolina, in the Department of Biological Sciences, Columbia SC 29208. As a public service, the Herbarium offers free plant identifications. For more information, visit www.herbarium.org or call 803-777-8196, or email nelson@sc.edu.

[Answer: “Holly fern,” Cyrtomium falcatum]