in botany, a genus of the tetradynamia filiculosa clas. The pod is entire and somewhat oval, with plain valves, and a parallel dissepimentum; it has no stylus. There are six species, three of them natives of Britain, viz. the verna, or common whitlow-gras; the muralis, or speedwell-leaved whitlow-gras; and the incana, or wreathen-podded whitlow-gras.