(from *twice*, and *a man*), the name of the second clas in Linnæus's sexual system, consisting of hermaphrodite plants; which, as the name imports, have flowers with two stamens or male organs.

The orders in this clas are three, derived from the number of styles or female parts. Most plants with two stamens have one style; as jeffamine, lilac, privet, veronica, and bastard alaternus: vernal grass has two styles; pepper, three.