1973. The name has many synonyms. In particular, the species was previously treated as a subspecies of Anemone nemorosa, now known as Anemonoides nemorosa. Anemonoides quinquefolia is a member of a species complex that includes A. grayi, A. lancifolia, A. oregana, and A. piperi. Members of the complex have remarkably similar morphology. Infraspecific taxa The Flora of North America accepts and treats two varieties of Anemonoides quinquefolia: A. quinquefolia var. quinquefolia, which occurs over the entire species range A. quinquefolia var. minima, which occurs only in North Carolina, Tennessee, Virginia, and West Virginia The two are distinguished mainly by the size of the achene (the fruit), the body of which is in A. q. var. minima as compared to in A. q. var. quinquefolia. Other sources accept additional varieties, such as A. quinquefolia var. bifolia, but Kew's Plants of the World Online lists no accepted infraspecific taxa for this species. Distribution Anemonoides quinquefolia is native to North America. It ranges from Manitoba across the Great Lakes region to Nova Scotia, south along the Appalachian Mountains to central Alabama. Further west there are isolated populations in Alberta, North Dakota, and Missouri. It prefers moist open woods, thickets, and clearings. It is also found along streams and occasionally in swampy areas. Ecology Anemonoides quinquefolia is a long-lived perennial geophyte that spreads by means of underground rhizomes. The small rhizomes are situated just below the surface in the humus-rich layer of decaying tree leaves. There the plant slowly spreads to form patches that can reach several feet in diameter. An individual plant may take 5 years or longer to flower. A. quinquefolia flowers between March and June depending on location. It is a spring ephemeral with a very short growing season. It emerges early in the spring, reproduces quickly, and dies back to its rhizome by midsummer. The flower of A. quinquefolia is nyctinastic, that is, the flower closes at night (and on cloudy days) and opens during the day. This habit protects the reproductive organs, maintains the viability of pollen, and may be a possible defensive strategy against herbivores. A. quinquefolia is a myrmecochore, that is, its seeds are dispersed by ants. Each seed has a fleshy structure called an elaiosome, a nutrient-rich appendage that attracts ants. The ranges of A. quinquefolia and A. lancifolia overlap in the southeastern United States where the two species interbreed. The resulting hybrids have intermediate characteristics,