This plant is not recorded in any of the references as existing in Pennsylvania. We are very close to positive in this identification, however, and there is a large patch of it in the Squaw Run Valley in Fox Chapel. It is primarily a Midwestern species, but it also occurs in other isolated and widely separated stands in the East. It resembles the Rue Anemone, Thalictrum thalictroides (and we mistakenly identified it that way when we first ran across it), but its even carpet of three three-parted leaflets identifies it, as do the invariably white five-petaled flowers (actually the “petals” are sepals) and the habit of forming a dense colony.
