Sabatia angularis
Sabatia angularis, commonly called rosepink, rose pink, square-stem rose pink or rose gentain is a biennial flowering plant in the Gentianaceae (gentain) family. It is native to central and eastern North America. Description
S. angularis grows  tall, although in the first year this biennial plant appears only as a low rosette of leaves. In the second year, one or more stems rise from the basal leaves. The stems are 4-sided, appearing as a square in cross section, and glabrous, with flexible, thin wings on the edges. The lower part of the main stem is unbranched, with branches growing primarily from leaf nodes on the upper part. The leaves are opposite, simple, entire (without teeth), glabrous, ovate to ovate-lanceolate, and measure up to about  long and  wide. The plant blooms from June to September with fragrant pink (occasionally white) flowers that are up to  across. The flowers have 5 petal-like obovate lobes. Yellowish triangular markings on the inner edge of the lobes give the appearance of a star in the middle of the flower. After the flowers fade, the plant produces seed capsules that contain numerous tiny seeds. Seeds are spread by the wind, and the plant will reseed itself. Etymology
The genus name honors Liberato Sabbati, an 18th century Italian botanist. The specific epithet is Latin for "angular", referring to the square stems. Distribution and habitat
It is geographically widespread in the United States, in the southern U.S. from Arizona in the west all the way to the east coast, and in the northern U.S. from Illinois in the west to Massachusetts in the east. It is native to Ontario but it is believed to be extirpated. S. angularis is found in a variety of habitats, in glades, along roadsides, in fields, and along the margins of woods. References

angularis
Flora of the United States
Plants described in 1753
Taxa named by Carl Linnaeus