This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Shrubs, with odd-pinnate leaves, the large stipules conspicuous. Flowers perfect, in terminal panicles. Calyx-tube hemispheric, its 5 lobes imbricated, early reflexed. Petals 5, imbricated. Stamens numerous, borne on the margin of the disk. Pistils mostly 5, opposite the calyx-lobes, connate below; styles terminal or nearly so; ovules several, pendulous. Follicles thin, dehiscent along both sutures. Seeds few, with endosperm. [Greek, referring to the pinnately compound leaves.]
About 3 species, natives of Asia, the following typical.
Spiraea sorbifolia L. Sp. Pl. 490. 1753.
Schizonotus sorbifolius Lindl.; Steud. Nomencl. Ed. 2, 2: 531. 1841.
Stems 6° high, or less, little branched. Leaflets 13-21, lanceolate, acuminate, finely double-serrate, glabrous or more or less stellate-puberulent; panicle often 1° long, densely very many-flowered; calyx-lobes ovate; petals white, obovate, about 1 1/2" long; filaments about twice as long as the petals; follicles oblong, pilose; styles recurved.