Sub-category: Smartweed family
Generally considered an invasive species and pest for its ability to grow very quickly and cover-over and envelope an entire area, often starving other plants of sunlight and nutrient. It has a reddish stem that is armed with downward pointing hooks or barbs which are also present on the underside of the leaf blades. The light green colored leaves are shaped like an equilateral (equal-sided) triangle and alternate along the narrow, delicate stems. Distinctive circular, cup-shaped leafy structures, called ocreas, surround the stem at intervals. Flower buds, and later flowers and fruits, emerge from within the ocreas. Flowers are small, white and generally inconspicuous. The fruits are attractive, metallic blue and segmented, each segment containing a single glossy, black or reddish-black seed.
Occurs in a wide variety of habitats including: open and warm areas, along the edges of woods, wetlands, stream banks, and roadsides, uncultivated open fields, parks, and fence lines.