Hydropiper
Pronunciation : Hy"dro*pi`per
Part of Speech : n.
Etymology : [NL., fr. Gr. "y`dwr water + L. piper a pepper.] (Bot.)
Definition : Defn: A species (Polygonum Hydropiper) of knotweed with acrid foliage; water pepper; smartweed.
Source : Webster's Unabridged Dictionary, 1913