pinweed

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

• noun Any of various North American perennial plants of the genus Lechea, having narrow leaves and numerous small flowers.

from The Century Dictionary.

• noun Any plant of the genus Lechea (which see), so called from the slender round stem and branches.
• noun The stork's-bill or alfilerilla, Erodium cicutarium.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot.) Any plant of the genus Lechea, low North American herbs with branching stems, and very small and abundant leaves and flowers.

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

• noun Any plant of the genus Lechea, low North American herbs with branching stems, and very small and abundant leaves and flowers.