Flower:

Loose cluster of stalked flowers (raceme) more or less evenly spaced along the top of the stem, often with a few lateral racemes from the base of the cluster and/or the upper leaf axils. Flowers are 1/8 to ¼ inch across, have 2 white to pinkish petals each 1.6 to 2.9 mm long, notched to about half their length, with 2 green egg-shaped sepals about the same length that bend back away from the flower. In the center are 2 white stamens slightly longer than the petals. Beneath the flower is a hairy ovary. Flower and cluster stalks are sparsely covered in short hairs, at least some of which are gland-tipped.

Leaves and stem:

Leaves are opposite with pairs at right angles to the pair below, 2 to 6 inches (5 to 16 cm) long and to 3+ inches (2.5 to 8.5 cm) wide, minutely toothed around the edges, narrowly to broadly egg-shaped to oblong, tapering to a pointed tip, on a stalk 1 to 2 inches long. Leaves become rather smaller towards the top of the plant. Stems are single, erect, mostly hairless below the flower clusters. Colonies can form from horizontal, underground stems (rhizomes).

Fruit:

Fruit is a capsule 2.8 to 4.5 mm long and covered in hooked hairs that attach themselves to anything that passes by. When mature, the capsule is pear-shaped to nearly round, with several distinct ribs or grooves.

Notes:

Enchanter's Nightshade, also known as Circaea lutetiana, spreads by both seed and rhizomes, often creating small colonies in woodlands across much of Minnesota. Beware walking through the woods in late summer when this has mature fruit or you may end up with tons of it stuck to your clothes, or in your pet's fur.

There are 2 recognized subspecies: subsp. canadensis is the North American species and subsp. quadrisulcata (C. quadrisulcata) its Eurasian counterpart. Closely related is Alpine Enchanter's Nightshade (Circaea alpina), a much smaller plant which has open flowers all clustered at the top of the raceme rather than along the stem, rarely gets more than 10 inches tall at maturity, has fruit lacking ribs/grooves, leaves are more coarsely toothed, and favors cool, moist woods and swampy places, often found on moss-covered rocks and logs. The two can hybridize, the hybrid (C. ×sterilis) having intermediate characteristics.