Sabatia campestris

Sabatia campestris (Texas Star; also Prairie Rose-gentian, Prairie Sabatia, Meadow Pink) is a species of Sabatia, native to the south-central United States, from Texas east to Mississippi and north to Iowa and Illinois. It is also locally naturalized in New England. It is an annual plant growing to 15–25 cm tall with pairs of opposite leaves 8
Found on http://en.wikipedia.org/wiki/Sabatia_campestris
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