Corolla with morphologically different petals is seen in

In fabaceae, the corolla has morphologically three different types of petals. The largest is called as standard petal or vexillum present towards the posterior side and completely outside. The two lateral petals known as wings or alae have intermediate size and have one margin outside and one margin inside. The two anterior petals are smallest known as keel or carina which fuse with margins and form a boat shaped structure in which the sex organs are protected. ex: bean and pea.