Flower:

Small clusters of a few stalked flowers, mostly opposite a leaf along branching stems. Flowers are ¼ to 1/3 inch across with 5 white petals that are fused at the base, the triangular lobes spreading into a star shape, or strongly curled back. The petal base is tinged purplish green with a streak of yellow. Protruding from the center is a column of stamens with long, yellow tips. The calyx is less than ¼ inch long and has 5 triangular lobes. The calyx, flower stalks and outer surface of the petals are densely covered in sticky glandular hairs.

Leaves and stems:

Leaves are 1½ to 3 inches long, 1 to 2 inches wide, egg-shaped to somewhat triangular, pointed at the tip and a rounded or wedge-shaped base with a short taper to a slightly winged stalk. Edges are densely hairy, often wavy, and are toothless or with a few shallow lobes or large, rounded teeth.

Surfaces are variously covered in sticky glandular hairs as well as dots of glands, and typically with long hairs along the major veins on the underside. Stems are many branched, erect or more often sprawling, and densely hairy.

Fruit:

Fruit is a round berry, ¼ to 1/3 inch in diameter, initially green becoming opaque greenish brown at maturity. Inside are numerous, flattened seeds. The calyx enlarges as fruit develops, the lobes encasing about half the fruit then spreading out when fruit is ripe.

Notes:

An uncommon weed in Minnesota, this South American native is more widespread in the western US and is a serious pest of potato fields, acting as a reservoir for aphids and potato leafroll virus. This species is listed in many references as Solanum sarrachoides, and it is apparently under debate whether this is a synonym or a name that should be limited to species in South America. The DNR does not list this species as being present (or persisting) in Minnesota under either name but it is obviously here and we have chosen to follow Michigan Flora and call it S. physalifolium. Hairy Nightshade is similar to Black Nightshade (Solanum ptychanthum), a weedy native that is far more common and easily distinguished by its hairless to sparsely hairy leaves and stems.