Flower:

Flat clusters at the tips of branching stems in the upper plant. Flower structures are about 3/8 inch across with mostly 5 white (sometimes 3 or 4), petal-like appendages, each having a green, oblong to kidney-shaped gland at the base. In the center are numerous, tiny male flowers with yellow-green stamens, surrounding a single green female flower with an arcing, divided style.

At the base of a cluster are 2 or more leafy bracts with a broad band of white edging, sometimes entirely white. The calyx is densely hairy.

Leaves and stems:

Leaves are up to 3½ inches long and to 1½ inches wide, toothless, hairless or sparsely hairy, oblong to elliptical, pointed at the tip, rounded at the base, and stalkless. Attachment is alternate except in the flowering branches, where they may be opposite or whorled.

Stems are unbranched except in the flower clusters, light green, hairless or nearly so in the lower plant, often with long, spreading hairs in the upper plant. Stems contain a milky sap that can be very irritating to skin.

Fruit:

Fruit is a round to egg-shaped, 3-sectioned capsule, about 1/8 inch long, covered in short hairs, each section containing one seed. The capsule dries to dark gray.

Seeds are 3.7 to 3.9 mm long, oval to egg-shaped to nearly round, with a conspicuous brown ridge down one side. Color is variable, from nearly white to gray to orange-tan. The surface texture is a fine network, with or without scattered ridges that give a bumpy texture.

Notes:

Snow-on-the-mountain is primarily a Great Plains species, considered introduced east of Minnesota and west of the Rocky Mountains, where its known to escape cultivation and become weedy. It is easy to identify with the white-edged leafy bracts around the flower clusters.