Small, glabrous, annual or possibly short-lived perennial herbs, often stoloniferous. Leaves usually radical by suppression of internodes, rarely opposite on new stolons, with a long slender petiole dilated at the base, and a small to large, palmately veined, entire, glandular-punctate blade shorter than, rarely equalling, the petiole. Flowers solitary in leaf-axils at base of plant, with bracts and bracteoles absent. Calyx-tube 5-angled, equally 5-toothed, or rarely in depauperate plants 3- or 4-merous; corolla more or less actinomorphic, campanulate, just exserted from the calyx, lobes 5, almost equal; stamens 4, anthers 1-locular; stigma obscurely 2-lobed, subcapitate. Capsule almost entirely surrounded by the enlarged persistent calyx, septum incomplete, absent in the upper half; seeds numerous, striate-reticulate.
About 15 species, in temperate regions of both Hemispheres; 3 species (all native) in Australia
The placement her of Limosella in Scrophulariaceae is tentative but is based on apparent nearest associations using DNA evidence. It is sometimes included in Phrymaceae or Plantaginaceae to where many genera of 'old' Scrophulariacae have been dispersed.