lousewort

any plant belonging to the genus Pedicularis, of the figwort family, as the wood betony, formerly supposed to cause lice in sheep feeding on it: one species, P. furbishiae Furbish lousewort, of parts of Maine and New Brunswick, Canada, having finely toothed leaves and a cluster of yellow flowers, is endangered and was thought to be extinct until specimens were discovered in 1946 and again in 1976.