Spigelia alabamensis, commonly known as Alabama pinkroot, is a species of flowering plant in the family Loganiaceae. It is endemic to Alabama in the southeastern United States, where it is restricted to dolomite glades in Bibb County.
Spigelia alabamensis is a perennial herb that grows in clumps and produces tubular flowers characteristic of the genus Spigelia. It typically occurs in shallow, rocky soils and may be locally abundant in suitable habitat.
Flowering occurs from May through June.
The species was originally described as Spigelia gentianoides var. alabamensis by K. Gould in 1996. It was later elevated to species rank as Spigelia alabamensis by K. G. Mathews and A. S. Weakley in 2011.
Spigelia alabamensis is one of several narrowly endemic taxa associated with the Ketona dolomite glade system of Bibb County, Alabama.
Spigelia alabamensis is known only from Bibb County in west-central Alabama.
It occurs in Ketona dolomite glades, a distinctive calcareous outcrop system formed on unusually pure Cambrian dolomite. Soils in these habitats are shallow, alkaline, and rich in calcium and magnesium but low in nutrients.
The species grows in open glades as well as along glade margins and forest edges, and may also occur in partially shaded conditions, where flowering can be more prolific.
Spigelia alabamensis is a narrow endemic with a highly restricted range of less than 100 km<sup>2</sup>. It is ranked as G2 (globally imperiled) and S2 (imperiled within Alabama).
The species is known from approximately 6âÂÂ20 occurrences, with around 12 extant populations documented. Total population size is estimated at between 2,500 and 10,000 individuals, though only a portion of this has been directly surveyed.
Threats include land development, livestock grazing, trash dumping, and forestry activities. Several populations occur on protected lands, including sites managed by conservation organizations, which contributes to the species' relative short-term stability.