spiraea (spĪrēˈə) [key], any plant of the genus Spiraea, Northern Hemisphere deciduous shrubs of the family Rosaceae (rose family). Most are indigenous to central and E Asia, whence come most of the popular ornamental species, e.g., the bridal wreath ( S. x prunifolia ), native to Japan, and its similar hybrid S. vanhouttei. In these species the fragrant, spirelike flower clusters typical of the genus are borne on long, arching branches. Spiraeas native to North America include the hardhack, or steeplebush ( S. tomentosa ), a local source of astringent and tonic, and the meadowsweets (several species). The name meadowsweet is also applied to the related genus Filipendula, tall, hardy perennials (also often cultivated) formerly classified as Spiraea because of the similar showy blossoms. Filipendula includes the Eurasian dropwort ( F. hexapetala ), the queen of the meadow ( F. ulmaria ), now naturalized in the United States, and the North American queen of the prairie ( F. rubra ). Spiraeas are classified in the division Magnoliophyta, class Magnoliopsida, order Rosales, family Rosaceae.