it's a northern starflower.
The Starflower: A perennial herb, the Starflower is from 3-25 cm tall (average height: 4 inches). The 4-7 leaves are lance shaped, slender and noticeably veined. Individual leaves are 3-11 cm long, and arranged in a whorl at the tip of the stem. The stems typically have several tiny, alternate, leaves. Most plants will have a single flower though there may be as many as three, each on a long, slender stalk 2-5 cm long, that rises well above the whorl of leaves. The corolla is white, deeply 7-lobed, the lobes slenderly pointed, 8-14 mm long, and spreading like a 7-pointed star. The fruit is a round, berry-like capsule, 6-8 mm in diameter, splitting by five valves and having many tiny seeds. Flowering period : May to June; fruiting period: June to July.