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Cespitose Knotweed (Polygonum cespitosum)

• Family: Smartweed (Polygonaceae)
• Flowering: June-October.
• Field Marks: This species has a smaller stature than any of the other smartweeds. It also has short, slender spikes of rose-pink flowers.
• Habitat: Open area in moist soil.
• Habit: Annual herb with fibrous roots.
• Stems: Usually erect, branched or unbranched, slender, usually smooth, up to 10 inches tall.
• Leaves: Alternate, simple, lanceolate to ovate, pointed at the tip, tapering to the base, hairy along the edges and on the veins of the lower surface, without teeth, up to 1 1/2 inches long; sheath with fine bristles at the tip.
• Flowers: Borne in short, cylindrical spikes up to 1 1/2 inches long, rose-pink.
• Sepals: 5, rose-pink, petal-like.
• Petals: 0.
• Stamens: 3-9.
• Pistils: Ovary superior.
• Fruits: Achenes triangular, shiny, up to 1/8 inch long.