It is composed of dense, tightly packed branches. Forms extensive
shrublands, alone or coexisting with other shrubs, such as the creeping juniper (
Juniperus communis subsp.
nana) in the high siliceous mountains, and almost always above forest level or coexisting with
Scot pines. The leaves fall early so the stems are often bare; the lower ones are trifoliate, without
petiole; the floral ones are simple and also seated. Flowers yellow, small, (9–12 mm) single or in pairs in the axil of the leaves, forming a more or less dense cluster at the termination of the branches supported by a 2–6 mm
head.
Calyx membranous, bell-shaped and hairy. The
corolla is butterfly-like, with a rounded upper
petal. The fruit is a
legume of 15 to 30 mm, straight or somewhat curved, very compressed laterally and covered with hairs applied to its surface. It flowers from May to July.
Cytisus oromediterraneus dominates the vegetation of the oromediterranean floor in Gredos, it can cover the highest north-facing slopes of the supramediterranean; in fact, from some points of Gredos, such as the road leading to the platform, it can be clearly seen how the north-facing slopes are covered by the Pyrenean broom, while those facing south are inhabited by the hiniesta and/or the white broom. In the coexistence zone between the Pyrenean broom and the white broom it is possible to find individuals with very light yellow flowers that are interpreted as hybrids between the two species. Finally, in the western, most sectors of the Central system, two other very thorny shrubby fabaceae, whose optimum is in the oromediterranean together with the Pyrenean broom, can appear on the north-facing supramediterranean slopes, the common broom (
Echinospartum barnadesii) and the Iberian broom (
Echinospartun ibericum). The clearings of piornales are mainly occupied by various herbs and shrubs, among which we highlight the attractive
viborera salmantina (
Echium salmanticum).
Boraginaceae, endemic to the western half of the mountain range, the
ortegia (
Ortegia hispanica, caryophilic), the lavender (
Lavandula pedunculata, Lamiaceae), the thyme (
Santolina rosmarinifolia,
Asteraceae), the aster with rice leaves (
Aster sedifolius,
Asteraceae) and the pink-flowered foxglove (
Digitalis thapsi,
Plantaginaceae), species that also mostly inhabit the cleared thickets of the oak forest floor and can ascend the sunny slopes to reach the Pyrenean broom. == Observations ==