Mountain broom, Piorno serrano

Citysus is one of several genera in the tribe Genisteae which are commonly called brooms.
They are extensive shrubs with close packed twigs producing masses of brightly yellow coloured, pea-like flowers, which alone or associated to other shrubs like Juniperus communis. The fruit is a hairy legume 15-30 mm long, slightly curved, and the leaves are small and spear shaped