knotgrass(redirected from allseed)
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(Polygonum aviculare), a plant of the family Po-lygonaceae. An annual with a very variable erect or prostrate stem, knotgrass has entire and alternate leaves. The flowers, which are solitary or few, are in the leaf axils. The perianth segments are greenish with white or pink margins.
Knotgrass grows almost everywhere—along roads, in pastures, and as a weed in crops. It is a valuable pasture plant for cattle and poultry, since it withstands trampling and close grazing well. An extract from the grass is used as a styptic and diuretic. Knotgrass is considered by many to be an aggregate species, including a large number of small species.