The flowers are trimerous, radially symmetric. The small flowers are regular and trimerous to pentamerous. The zygomorphic, trimerous, nodding flowers grow singly and are terminal on the stems. That group is characterized by trimerous flowers, pollen with one pore, and usually branching-veined leaves. Gynoecium tricarpellate, ovary epigynous (inferior), two trimerous androecial whorls with stamens 6, 5 or 1.