Santolina rosmarinifolia, the holy flax, is a species of flowering plant in the daisy family Asteraceae, native to south western Europe. It is a dense, compact evergreen shrub growing to 60 cm (24 in) tall and wide, with narrow, aromatic green leaves and tight yellow composite flowerheads carried on slender stalks above the foliage, in summer. The specific epithet rosmarinifolia describes the leaves' passing resemblance to those of rosemary, a distantly related group of plants.