- flowers leathery, greenish or reddish-brown, 5-lobed (2 upper, 2 lateral, 1 lower)
- stamens 4, sterile filament dilated at summit and lying under the upper corolla lip
- infloresence terminal, a loose compound cyme
- leaves opposite, petiolate, serrate to incised
- blades ovate or lance-ovate
- stems 4-angled