Stenanthium tennesseense
Stenanthium tennesseense, the Tennessee death-camas, is a species of flowering plant in the family Melanthiaceae. It is endemic to central Tennessee in the southeastern United States.
Description
Stenanthium tennesseense is a perennial herb arising from an underground bulb. Like other members of the genus, it produces narrow, grass-like leaves and small, star-shaped flowers arranged in a branched inflorescence.
The species is characterized by a branched panicle with relatively densely arranged flowers. Tepals are typically obovate with rounded to obtuse tips.
Flowering occurs from July to August and may extend into early autumn.
Taxonomy
The species was described in 2017 by B. A. Sorrie and A. S. Weakley.
It was previously included within Stenanthium leimanthoides (formerly treated under Zigadenus), but was recognized as a distinct species based on morphological and geographic differences.
The genus Stenanthium comprises several morphologically similar species in eastern North America, making inflorescence structure, floral morphology, and habitat important for species delimitation.
Distribution and habitat
Stenanthium tennesseense is endemic to central Tennessee, occurring on the Cumberland Plateau and Eastern Highland Rim.
It grows primarily in wet meadows, pine woodlands, and other moist, acidic habitats, including boggy or palustrine environments.
Distinction from related species
Stenanthium tennesseense is most closely related to Stenanthium leimanthoides and Stenanthium diffusum, but differs in several key characters.
It can be distinguished by its obovate tepals with rounded or obtuse tips, as well as by its branched panicle with moderately dense flowers. In contrast, S. diffusum has lanceolate tepals with acute tips and a much more diffuse inflorescence with widely spaced flowers.
Ecologically, S. tennesseense occurs in wet meadow and woodland habitats, whereas S. diffusum is restricted to shaded sandstone rockhouses with highly stable microclimates.
Taxonomically, S. tennesseense was segregated from S. leimanthoides, which differs in characters such as pedicel bract length and leaf width, as well as a broader geographic distribution extending beyond Tennessee.
Conservation
Stenanthium tennesseense is considered imperiled (G2) by NatureServe.
The species is restricted to a relatively small geographic range and is known from approximately 6–20 occurrences, with about 20 documented collections.
Although no immediate threats have been identified at all sites, its dependence on wet meadow and forested wetland habitats makes it vulnerable to habitat alteration, including drainage, land conversion, and changes in hydrology.