IVA, in botany: A genus of the pentandria order, belonging to the monoclea class of plants; and in the natural method ranking under the 49th order, Composita. The male calyx is common and triphyllous; the florets of the disc monopetalous and quinquefid; the receptacle divided by small hairs. There is no female calyx nor corolla; but five florets in the radius; two long styles; and one naked and obtuse feed.