Guiera is a flowering plant genus in the family Combretaceae. Guiera senegalensis is the only species in the genus. The plant produces the tannin 3,4,5-Tri-O-galloylquinic acid and several alkaloids of the harman family. Hydraulic redistribution (HR): When grown as a companion plant with millet water drawn up by Guiera senegalensis during the night is excreted by its roots and available to the millet, dramatically increasing its yield.