Biscutella sempervirens L.
Diagnostic description:
An erect, tomentose perennial. Stems up to 50 cm tall, arising from a basal rosette. Leaves mostly basal, oblong-lanceolate to lanceolate, densely hairy. Margins sinuate-toothed, sometimes pinnately lobed. Stem leaves very small; the upper ones linear, entire. Flowers with four petals, yellow, up to 1 cm across. Silicula usually less than 10 mm across, but can be larger.
Distribution:
Local: Common and widespread throughout Gibraltar, though rather scattered.
Global: Found in south-east Spain.
Ecology:
Flowers between March, April, May and June.
Habitat:
Grows on stony ground and from limestone crevices; waysides.