Starflower (Trientalis borealis) is a 4-inch high plant that doesn’t last very long and has small flowers, typically just one or two. The leaves are in a whorl, commonly of seven leaves and the small white flowers usually have seven petals. I don’t know of any other plants that grow in sevens, but maybe there are some. Another feature of starflower that is unusual is the flower stalks: at about an inch long, they are as slender as a fine thread. You can barely see them.