A low, procumbent, deciduous shrub a few inches high, but sometimes erect, the triangular stems without down, but with thin transparent wings. From the stems arise erect flowering twigs 1 to 3 in. long, bearing a single flower in each of the four to ten terminal leaf-axils. Leaves linear-lanceolate to narrowly ovate, glabrous, pointed or bluntish, 1⁄4 to 1 in. long, 1⁄16 to 3⁄16 in. wide, dark green with thin transparent margins. Flowers clear bright yellow; standard petal, roundish ovate, 1⁄4 in. wide; keel and wing petals about as long. Pods 1 in. long, 3⁄16 in. wide, glabrous, containing four to seven seeds. Bot. Mag., t.9574.
Native of northern and central Italy eastward and south-eastward to Slovenia, W. Rumania, and the Balkan Peninsula; introduced long ago and cultivated at Kew in 1850. It went out of cultivation, but at the Chelsea Show of May 1932 a group of young plants in a pan were shown by G. P. Baker of Sevenoaks, charmingly in flower, under the name “G. triquetra”. It was originally named in 1802 from a plant found on the island of Palmaria, near Spezia in Italy, but it is also widely spread on the mainland. It is essentially a plant for a ledge in the rock garden, where it will spread 2 to 3 ft wide. The distinctive characters are (in combination) its prostrate habit, triangular stems, simple leaves, axillary blossoms, and its entirely glabrous parts. It is allied to G. lydia (q.v.).
The name G. triquetra was given to this broom by Waldstein and Kitaibel in 1805, but it had already been used by L’Héritier in 1784 for quite a different shrub with trifoliolate leaves and therefore has no standing. The true G. triquetra L’ Hérit. is figured in Bot. Mag., t. 314, and is said by Aiton to have been cultivated in England by a Mr Ord as long ago as 1770. It does not appear to exist in the wild and could be a hybrid between Cytisus monspessulanus and Genista tinctoria.