The leaves are usually alternate and compound, in the Mimosoideae and the Caesalpinioideae commonly bipinnate (e.g. "Acacia", "Mimosa"). In many species the leaves have structures evolved to attract ants, that, being predatory, protect the plant from herbivore insects. Extrafloral nectaries -a gland secreting nectar -are common among the Mimosoideae and the Caesalpinioideae and are also found in some Faboideae (e.g. vetches "Vicia sativa"). Fabaceae are typically entomophilous plants (i.e. they are pollinated by insects) and the flower are usually showy to attract the pollinators.