WordNet sense 1 (annual with broadly ovate leaves and slender drooping spikes of crimson flowers; southeastern Asia and Australia; naturalized in North America):

kiss-me-over-the-garden-gate, prince's-plume, princess feather

WordNet sense 2 (tall showy tropical American annual having hairy stems and long spikes of usually red flowers above leaves deeply flushed with purple; seeds often used as cereal):

gentleman's-cane, purple amaranth, red amaranth