beggar's lice

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of several plants, such as the stickseed, having small, often prickly fruits that cling readily to clothing or animal fur.
2. n. The fruit of any of these plants.

Century Dictionary and Cyclopedia

1. n. An English name of Galium Aparine, or goose-grass, given to it because its burs stick to the clothes, and somewhat resemble lice.
2. n. The name given in the United States to species of Bidens and to Echinospermum Virginicum, the seeds of which have barbed awns which cling persistently to clothing. Also called beggar's-ticks.
3. n. A name of the European stickseed, Lappula Lappula; of the hound's-tongue, Cynoglossum officinale; of the species of Meibomia (see beggar-weed, 2); and probably of other plants with adhesive seeds or pods.

GNU Webster's 1913

1. (Bot.) The prickly fruit or seed of certain plants (as some species of Echinospermum and Cynoglossum) which cling to the clothing of those who brush by them.

WordNet 3.0

1. n. any of various tropical and subtropical plants having trifoliate leaves and rough sticky pod sections or loments
2. n. Eurasian and North American plants having small prickly nutlets that stick to clothing