Hart's-tongue (Seolopendrium), a genus of widely distributed ferns, of which one species, S. vulgare, is a native of Britain, and is common in many parts of the country, in moist woods, shady banks, caves on the seashore, and other cold and damp situations. Its fronds are in general undivided—although sometimes forked—from a few inches to 2 feet in length, and from 1 to 3 inches in breadth. The sori are in transverse lines on the lateral veins. Fine plants of this fern are very ornamental, and attain their greatest luxuriance in winter.