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 stiff spine-like branches, simple, linear stiff Very prickly leaves, and large yellow solitary or racemed flowers. Calyx membranous, mostly yellow, divided nearly to its base into 2 concave lips; upper lip mostly 2-toothed, and lower 3-toothed; teeth short. Standard ovate; wings and keel oblong, obtuse. Stamens monadelphous; anthers alternately longer and shorter, the shorter versatile. Ovary sessile, several-many-ovuled; style somewhat incurved, smooth. Pod ovoid, oblong or linear. Seeds strophiolate. [The ancient Latin name.]
About 20 species, natives of eastern Europe, the following typical.
Ulex europaeus L. Sp. Pl. 741. 1753.
Much branched, bushy, 2°-6° high, more or less pubescent. Branchlets very leafy, tipped with spines; leaves prickly, 2"-7" long, or the lowest sometimes lanceolate and foliaceous; flowers borne on twigs of the preceding season, solitary in the axils, 6"-8" long, the twigs appearing like racemes; pedicels very short, bracted at the base; calyx a little shorter than the petals, minutely 2-bracteo-late; pod few-seeded, compressed, scarcely longer than the calyx.