Perennial herbaceous plant (Curcuma longa; family Zingiberaceae), native to southern India and Indonesia. Its tuberous rhizomes have been used from antiquity as a condiment, as a textile dye, and medically as an aromatic stimulant. The rhizome has a pepperlike aroma and a somewhat bitter, warm taste. It colours and flavours prepared mustard and is used in curry powder, relishes, pickles, spiced butters, and numerous culinary dishes. Paper tinged with turmeric turns from yellow to reddish brown when an alkali is added to it, thus providing a test for alkalinity.