hound’s-tongue, any of 75 species of the plant genus Cynoglossum, in the family Boraginaceae, including the bright-blue-flowered Chinese forget-me-not (C. amabile), native in mostly temperate areas of the New World and Old World. They are named for their usually rough, tongue-shaped leaves.
Two purplish-red-flowered, European species of hound’s-tongue, C. officinale and C. germanicum, are widespread along roadsides and in dry soils, the former naturalized in North America. They are 60 to 90 cm (2 to 3 feet) tall and produce curving sprays of small, five-lobed blooms and sticktight clusters of spined seeds.