Plants in the anacardiaceae (sumac or cashew family family) are mostly trees or shrubs, native to tropical places, in Asia, Africa and the Americas. Nearly 40 species occur in the US, about half of which are native; rhus and toxicodendron are the two main genera. Plants are resinous and often poisonous. Leaves are usually alternate, and varied in form, including odd-pinnate, trifoliate and simple. The bracted flowers consist of a calyx, of between three and seven lobes, and a corolla with the same number of petals. Flowers may be pistillate, staminate or perfect (with both pistils and stamens). Stamens number the same as the petals, or twice as many.