clearweed

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

• noun Either of two eastern North American annual plants (Pilea pumila or P. fontana) having short drooping clusters of tiny greenish-white flowers and translucent stems and leaves.

from The Century Dictionary.

• noun The Pilea pumila, a low nettle-like plant of the United States, with a smooth, shining, and pellucid stem, growing in moist shaded places. Also called richweed.

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

• noun A herb with a clear stem; the richweed.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a plants of the genus Pilea having drooping green flower clusters and smooth translucent stems and leaves