The evolution of approximately half of the New World gesneriads has been partly by co-adaptation with bird pollinators, notably the humming bird family which is restricted to the Americas.
C forms a basal tube and is often spurred.
Inflorescences are racemes, cymes or solitary. Seeds many, with or without endosperm, and straight embryos. Habit usually herbs and shrubs, rarely trees and lianas, sometimes epiphytic. Underground parts are fibrous, woody tubers or scaly, rhizomatous aerial stolons. Leaves are opposite or alternate, sometimes basal, simple and entire or toothed.