prince's feather

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

• noun Either of two plants (Amaranthus hypochondriacus or A. cruentus) having reddish foliage and dense panicles of brownish-red flowers.
• noun A tall plant (Persicaria orientalis) of Asia and Australia, having hairy stems, broadly ovate leaves, and long spikes of pink or rose flowers.