Plant of the Week

Prairie Trillium (Trillium recurvatum)

By Larry Stritch

All trillium species belong to the Liliaceae (lily) family and are rhizomatous herbs with unbranched stems. Trillium plants produce no true leaves or stems above ground. The “stem” is actually just an extension of the horizontal rhizome and produces tiny, scalelike leaves (cataphylls). The aboveground plant is technically a flowering scape, and the leaf-like structures are actually bracts subtending the flower. Despite their morphological origins, the bracts have external and internal structure similar to that of a leaf, function in photosynthesis, and most authors refer to them as leaves.

Trilliums are divided into two major groups, the pedicellate and sessile trilliums. In the pedicillate trilliums, either the flower sits upon a pedicel that extends from the whorl of bracts, “erect” above the bracts, or “nodding” recurved under the bracts. In the sessile trilliums, there is no pedicel and the flower appears to arise directly from the bracts.

Prairie trillium falls within the sessile trillium group and typically flowers from early to late March to late May. Prairie trillium exhibits many shades of red to red-violet and a number of color forms such as bronze and forma shayi with yellow petals.

Prairie trillium is found on the inner Gulf coastal plains of the southeastern United States north through upper south continuing into the Midwest. They inhabit rich mesic forests on rich calcareous soils and rich clayey soils on floodplains.

For More Information

• PLANTS Profile - Trillium recurvatum, Prairie Trillium
• Flora of North America: Trillium recurvatum
• Case, F.W., R.B. Case. 1997. Trilliums. Timber Press, Portland, OR.

Terrific Trilliums Species…