Helonias bullata (Swamp Pink) is a perennial rhizomatous herb and usually blooms from March to May. Its fragrant flowers are pink and occur in a cluster. It has dark evergreen, lance-shaped, and parallel-veined leaves that form a basal rosette.
It had previously been placed in the Family Liliaceae, but according to the 2003 APG II it is is in the Family Melanthiaceae along with Trillium and Paris, among others.
Swamp Pink is a federally threatened species that was historically distributed from Staten Island, New York to the southern Appalachians. It is the only species in its genus. Many extant populations suffer low genetic diversity.
Swamp Pink occurs in wetland habitats and it requires habitat which is saturated, but not flooded, with water. Typical areas include swampy forested wetlands which border small streams; meadows, and spring seepage areas. It is often found near conifers.
The Center for Plant Conservation has more information here: http://www.centerforplantconservation.org/collection/cpc_viewprofile.asp?CPCNum=2210
The original document is available at http://nargs.org/nargswiki/tiki-index.php?page=Helonias