Brilliant wildflower grows in coastal savannas | Mystery Plant

"Savanna" — there's no "h."

Of course, we all know Forrest Gump’s beautiful city with its midnight gardens, as well as the river that flows between Georgia and South Carolina, but a savanna is different.

In the Southeast, a savanna is an ecosystem situated in the coastal plain, largely dominated by pines (mostly longleaf pine), and featuring a variety of sandy soils, these periodically wet. Savannas have been known historically as some of the most biologically diverse habitats on our planet, featuring enormous numbers of plant and animal species.

A requirement for the development and continued existence of savanna habitat has been periodic fires, largely from lightning strikes, that would burn away undergrowth and shrubs, allowing the formation of a rich layer of herbaceous plants, including grasses, sedges, orchids, ferns, lilies, milkweeds, sunflowers, hatpins, meadow-beauties, and carnivorous sundews and pitcher plants, among other things, a number of which are very, very rare.

Historically, coastal savannas were known from southeastern Virginia all the way to Texas, but sadly, very few of the original savannas remain, having fallen away to progress and development, and to the suppression of natural forest fires.

Many of the plants native to them remain, however, but sometimes only along open ditch lines that are so common along our country roads. Although ditch lines along highways usually receive little acclaim, they can act as savanna remnants or "refugia," providing the last possible habitats for various plants (and animals) after the surrounding landscape has been altered.

Here's a savanna plant that is really spectacular. It's a milkweed, and sure enough, its tissues contain plenty of white, sticky latex, which gives this group of species its common name. The more common, and related, low-growing butterfly-weed is also a part of this group, but its sap is clear, not milky.

Our Mystery Plant (Savanna milkweed, Asclepias lanceolata) has a smooth, unbranched stem, up to 4 feet tall. Four or five pairs of skinny leaves will be found on the stem, with brilliant flowers in several clusters at the top. Each flower has five small sepals at its base, pretty much hidden by the five bright red petals.

Above each petal will be a bright red (or more commonly, orange) structure called a hood, with a sharp-pointed "horn" emerging from the top. Following the flowers, smooth, erect seed pods ("follicles") will form, these eventually releasing wind-borne seeds, floating by means of a tuft of silky hairs.

This species is a regular inhabitant of coastal savannas, or savanna remnants, and occurs from New Jersey south through Florida and west to Texas. If you'd like to see it in its natural landscape, you might investigate savanna sites at the Francis Marion National Forest (Berkeley and Charleston Counties, SC) or the Nature Conservancy's Green Swamp Preserve (Brunswick County, NC).

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, call 803-777-8175 or email [email protected].

This article originally appeared on Tallahassee Democrat: This milkweed grows in coastal savannas and ditch lines