Least trillium and its many varieties


Trillium pusillum var. pusillum NatureServe Global Status: Vulnerable (G3)| Photo From Richard LeBlond, N.C. Natural Heritage ProgramIn a few special places from Virginia to Arkansas, and south to Texas and Mississippi, the ground is scattered with delicate white and pink flowers shaped like pinwheels. Known as Carolina Least Trillium (Trillium pusillum), this widespread plant was once considered one species ranked as Vulnerable (G3).  However, Natural Heritage Program botanists across the range have worked with researchers to collect and identify plant specimens. In North Carolina, Misty Buchanan, the NatureServe Network’s North Carolina Natural Heritage Program Director, helped collect specimens in Wilson, Raleigh, and Smithfield NC. This data, along with examinations of physical characters, ecology, and the species’ range, reveal that Trillium pusillum is composed of five to nine varieties that span the various states. Three of the varieties were found in North Carolina: Carolina Least Trillium, Virginia Least Trillium, and Ozark Least Trillium (Trillium pusillum var. pusillum, Trillium pusillum var. virginianum, and Trillium pusillum var. ozarkanum).  With this new information, the North Carolina Plant Conservation Program has listed all 3 varieties as endangered in the state. This Trillium pusillum var. virginianumEndangered status allows the Plant Conservation Program to pursue conservation opportunities that will protect this species.

North Carolina’s nature preserves must include all three varieties to ensure that each one survives. Currently, two of the three varieties of Least Trillium are protected within State Parks and National Wildlife Refuges in the Coastal Plain of North Carolina.  However, the 3rd recognized variety (Ozark Least Trillium), which occurs in the mountains, does not occur on protected lands.  Recognizing the distinct variety in the mountains allows natural heritage botanists to search for suitable sites in the mountains, and work with landowners and conservation agencies to pursue voluntary protection opportunities. These conservation efforts, based on a scientific discovery from within the NatureServe Network, will ensure that all 3 varieties remain part of North Carolina’s natural heritage.

View a distribution map for Trillium pusillum populations

Trillium pusillum in North Carolina | NatureServe