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, often stiff or spiny, with 3-foliolate or 1-foliolate leaves, and showy clustered flowers, mainly in terminal racemes. Calyx 2-lipped, campanulate, the teeth short; standard ovate or orbicular; wings oblong or obovate; keel straight or curved. Stamens monadelphous; anthers alternately larger and smaller. Ovary sessile, many-ovuled; style incurved. Pod flat, oblong or linear, pubescent or glabrous, several-seeded; seeds strophiolate. [From Cythrus, one of the Cyclades, where the first species was found.]
About 45 species, natives of Europe, western Asia and northern Africa, the flowers very slightly different from those of Genista. Type species: Cytisus hirsittus L.
Spartium scoparium L. Sp. Pl. 709. 1753.
Sarothamnus scoparius Wimm.; Koch, Syn. Fl. Germ. 152. 1837.
Stiff, wiry, 3°-5° high, much branched, nearly glabrous. Branches elongated, straight, nearly erect, angled; lower leaves petioled, 3-foliolate, the leaflets obovate, acute, or mucronate-tipped, 3"-5" long, entire, narrowed at the base; upper leaves sessile, often 1-foliolate; stipules none; flowers bright yellow, nearly 1' long, in elongated terminal leafy racemes; pedicels solitary or 2-3 together, 3"-s" long; pod flat, glabrous on the sides, but ciliate on the margins, 1'-2' long; style slender, at length spirally curved.