USGS Home
Contact USGS
Search USGS

Virginia Buttonweed (Diodia virginiana)

• Family: Madder (Rubiaceae)
• Flowering: June-September.
• Field Marks: Members of the genus Diodia are recognized by their bristle-like stipules at the base of the leaves and only 1-3 flowers in the axils of the leaves. Virginia buttonweed is further distinguished by having only 2 sepals.
• Habitat: Along streams, wet meadows, low woods, wet ditches, around ponds, swamps, damp fields, marshes.
• Habit: Annual herbs from fibrous roots.
• Stems: Spreading or sprawling, much branched, 4-angled, usually smooth or hairy on the angles, up to 2 feet long.
• Leaves: Opposite, simple, elliptic to lanceolate, pointed at the tip, tapering to the base, without teeth, smooth, up to 2 inches long, up to 1/2 inch wide.
• Flowers: 1-3 in the axils of the leaves, white, about 1/3 inch across.
• Sepals: 2, green, united below.
• Petals: 4, white, united to form a tube 1/3 inch long, the lobes spreading.
• Stamens: 4, attached to the corolla tube and usually just barely protruding above it.
• Pistils: Ovary inferior.
• Fruits: Leathery, hairy, ellipsoid, 1/4-1/3 inch long, splitting into two 1-seeded segments.
• Notes: The fruits of this species are eaten by waterfowl.