Fls in terminal verticillate bracteate panicles, sts much reduced. Calyx 5-lobed, some or all of clefts extending almost to base. Corolla weakly zygomorphic, with short slightly oblique tube ± hairy within, and 5 spreading lobes, the posterior two shortest and overlapping the lateral ones in bud. Stamens 4, didynamous, inserted near base of corolla-tube, staminode minute, anther-cells apically confluent. Style long, stigma capitate. Capsule ovoid-conical, loculicidal; seeds ∞, reticulate. Low-growing perennial herbs with opp. us. strongly veined lvs. Some 24 spp., about 12 in South America, 1 in Tasmania, the N.Z. spp. endemic.

2n = 48