LOOSESTRIFE, in botany: A genus of the monogynia order, belonging to the pentandra class of plants; and in the natural method ranking under the 20th order, Rosaceae. The corolla is rotaceous; the capsule globular, beaked, and ten-valved. There are ten species, but only four are commonly cultivated in gardens. These are hardy, herbaceous perennials and biennials, rising with erect stalks from 18 inches to two or three feet high; garnished with narrow entire leaves; and terminated by spikes and clusters of monopetalous, rotated, five-parted spreading flowers of white and yellow colours.—They are easily propagated by seeds, and will thrive in any soil or situation.