Genista L. (1753), in the family Leguminosae subfamily Papilionoideae, contains around 100 species in Europe, the Canary Islands, and southwestern Asia. Description Trees to 6m, shrubs, or herbaceous perennials, sometimes spiny. The leaves are alternate, with 1 or 3 leaflets, usually falling early in the season to leave the plant bare. The flowers are pea-like, solitary or in tight or elongated heads, always yellow. Sepals 5, unequal, joined to form a 2-lipped calyx, the upper lip usually with 2 long teeth, the lower with 3 teeth. Petals 5, unequal, the uppermost a broad standard, the 2 outer wings, the 2 lowest forming a narrow keel that encloses the stamens, style, and ovary. Stamens 10, the filaments all joined to form a tube. Ovary superior, with 1 carpel containing several ovules; style 1. Pollination is by bees. The pods have usually several but sometimes only 1 or 2 seeds, without appendages. Key Recognition Features The seeds without appendages distinguish Genista from the similar Cytisus. Genista species all have yellow flowers. Evolution and Relationships Adenocarpus DC, mainly from Spain, the Canary Islands, and North Africa, are fine shrubs related to Genista, but are more leafy, with flowers in clusters on the tips of the branches and pods covered with glandular warts.
Ecology and Geography In stony, sometimes grassy or peaty, open places. Most species are from Spain and Portugal, but a few are distributed across Europe, and 12 are found in Turkey. Comment Many species are cultivated, including the tree-like
G. aetnensis (Biv.) DC from Sardinia and Sicily, which forms a lovely, small, weeping tree. Genista cinerea (Vill.) DC from Spain and Portugal is a graceful shrub with scented flowers. The dwarf, spreading G. lydia Boiss. from Turkey is popular for rock gardens. Genista tinctoria L., a herbaceous species found from England to Iran, is the dyer’s weed or woodwax; it was used in the past as a yellow dye, usually combined with woad (Isatis tinctoria L.) to produce a range of greens, including the so-called Kendal green. |
