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Gentian Pinkroot

Gavin Schotts, Auburn University
Gentian Pinkroot
Gentian pinkroot, also known as Spigelia gentianoides, is a small, long-lived flowering plant. It belongs to the Order Gentianales, which includes the economically important coffee plant and popular garden shrubs gardenia and oleander. The genus name honors Flemish anatomist Adriaan van den Spiegel and the species name is Greek for "gentian-like." Gentian pinkroot is critically endangered, with only five populations known to exist. Of that five, one occurs in Bibb County in west-central Alabama and one in Geneva County in southeastern Alabama, with the other three located in the Florida Panhandle. The population in Bibb County has been assigned to its own species, Spigelia alabamensis. The plant was formerly widespread as an understory species among many in the longleaf pine ecosystem.
The species was first discovered by pioneering botanist Alvan Wentworth Chapman in 1837 near the Apalachicola River in Florida. The plant was initially named S. floridana by Chapman but was later changed to S. gentianoides by Alphonse de Candolle in 1845 owing to its similar appearance to the genus Gentia.
Gentian Pinkroot Fruits
Gentian pinkroot grows in open spaces in fire-dependent forests, including the longleaf pine plant community that once covered much of the lower half of the state, as well as pine-oak-hickory woods. It typically grows to an average of 10-15 inches (25-40 centimeters) high. Gentian pinkroot grows from a fleshy rhizome and often forms clumps of numerous stems bearing simple, lance-shaped leaves in opposing pairs. Flowers, which appear between May and June, are tubular with light to dark pink petals with dark pink coloration along the edges of the petals. Gentian pinkroot flowers barely open for the duration of the flower's life and typically last just two to five days before they begin to wilt.
Gentian Pinkroot
Scientists are unclear about how the gentian pinkroot is pollinated. Various insects have been observed visiting its flowers during blooming, including butterflies, flies, and numerous species of bees. Because the flowers never fully open, insects must peel back the petals or wait until a larger insect does so. After a flower is pollinated, the petals fall off and a heart-shaped fruit develops during June into July. When the fruit is fully mature, it explodes and spreads numerous seeds away from the plant.
Gentian pinkroot was wiped out from much of its historic range when forests were cleared for agriculture. The main threats to gentian pinkroot are fire suppression, habitat loss, and invasive plants. All currently known populations are found in protected forests, such as Geneva State Forest in Geneva County. Without proper habitat maintenance, such as frequent proscribed burns, gentian pinkroot can be easily shaded out by taller, often invasive, plants.
Alabama Gentian Pinkroot
Because of its low population numbers, gentian pinkroot was listed as "endangered" by the U.S. Fish and Wildlife Service (USFWS) in 1990. Historically, there were 6 populations of gentian pinkroot. In 1994, a population of S. gentianoides, termed S. gentianoides var. alabamensis was found in Bibb County. The variant would later be split into its own species known as Spigelia alabamensis, or Alabama gentian pinkroot, by plant scientist Alan Weakley in 2011. The split was due to differences in plant shape and habitat from the other gentian pinkroot populations. This split resulted in the loss of federal protection status from the USFWS for the Bibb County population. Currently, Spigelia alabamensis lacks planning or funding for proper federal protection. A 2018 survey by Auburn University researchers found that the Geneva State Forest population nearly tripled, however, rising from 400 individual species to more than 1,200 individuals. The USFWS has listed gentian pinkroot as having a high recovery potential, meaning that with proper conservation management, it can be taken off the federally endangered list.

Additional Resources

Gould, Kathie R. "Systematic Studies in Spigelia." PhD dissertation, University of Texas at Austin, Texas, 1997.
Panama City Field Office, U.S. Fish and Wildlife Service. Spigelia gentianoides Gentian pinkroot 5-Year Review: Summary and Evaluation. Panama City, Fla.: U.S. Fish and Wildlife Office, 2008.
Weakley, Alan S., et al. "New Combination, Rank Changes, and Nomenclatural and Taxonomic Comments in the Vascular Flora of the Southeastern United States." Journal of the Botanical Research Institute of Texas 5, no. 2 (2011): 437-55.
Published:  February 14, 2019   |   Last updated:  February 14, 2019