allseed

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of several plants, such as knotgrass, producing numerous seeds.

from The Century Dictionary.

• noun A name given in Great Britain to several very different plants: Polycarpon tetraphyllum, a small plant found in the southwest of England; the knot-grass, Polygonum aviculare; Chenopodium polyspermum, found in waste places; Radiola Millegrana.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any of several unrelated plants that produce many seeds.