Perennial herbs, minutely, sometimes obscurely, gland-dotted. Leaves opposite, simple, 3-veined at the base, sessile. Inflorescences open racemes or spikes, flowers single, or rarely 2, in the axil of leaf-like bracts; bracteoles 2, inserted just below calyx. Sepals 5, free; corolla-tube symmetrical at base, neither swollen nor spurred, broad, more or less cylindric, apically upturned, limb more or less forward-directed, obscurely 2-lipped, upper lip 2-lobed, lower lip 3-lobed, without a palate; stamens 2, anthers adjacent, staminodes 2 or sometimes absent, filaments without spurs, anthers with 2 separate locules; stigma perpendicular to the style, with 2 broad equal flaps. Capsule 4-valved, dehiscing both septicidally and loculicidally, leaving a central column with some remnants of the septum attached, style shortly persistent; seeds numerous, not winged, reticulate.
20 species, in temperate areas of both Hemispheres; at least 5 species in Australia.
The Australian species need clarification in the context of a world revision; all species but G. pedunculata are questionably separated at the species level.
Observations of indumentum have been made from dried material and need anatomical verification. It is unclear whether the minute hairs occurring in varying abundance in most species are at first gland-tipped.