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The perennial Ruellia caroliniensis or Carolina wild petunia is 30-60 cm tall and is most easily recognized by the long calyx lobes and bracts positioned directly below the trumpet-shaped main flower (Hutchinson 2012). Petals range from lavender to pale blue. Flowering occurs from late spring through autumn and each bloom will open for approximately one day. Each fruit capsule produce about five seeds (Hutchinson 2012).

Ruellia caroliniensis is native to Texas, Oklahoma, Louisiana, Florida, Georgia, Kentucky, Tennessee, Alabama, South Carolina, North Carolina, Illinois, Indiana, Ohio, Pensylvania, West Virginia, Virginia, Maryland, New Jersey, and Delaware (NatureServe, 2013).

Due to considerable morphological variation, Ruellia caroliniensis can be difficult to classify. Although many characteristics vary dramatically within the species, leaf size, leaf shape and leaf margin, length of longest internode were studied (Long 1974: 1-2). Morphological variability was correlated with geographical distribution which may explain taxonomists giving names to different morphologies as local forms and varieties (Long 1974: 1-2, 5). Breeding in Ruellia caroliniensis appears to shift from primarily allogamous (cross-fertilization) in the south (central and southern Florida), to chiefly autogamous (self-fertilization) in its northern range (Virginia, Kentucky, Tennessee, North and South Carolina) (Long, 1974: 3, 6). Factors that are believed to cause this shift to autogamous breeding are variability in temperature and moisture and severe insect predation of fruits (Long, 1974: 6).


Hutchinson, M. 2012. Native plant owners manual. Ruellia caroliniensisCarolina wild petunia. Accessed: November 21, 2013.

Long, R. W. 1974. Variation in Natural Populations of Ruellia caroliniensis. Bulletin of the Torrey Botanical Club 101(1):1-6.

NatureServe. 2013. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Accessed: October 30, 2013.


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