Northern Prairie Wildlife Research Center
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.
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