Hormathophylla spinosa, formerly Alyssum spinosum, the spiny madwort, is a species of flowering subshrub in the genus Hormathophylla of the family Brassicaceae, native to open rocky sites in south-eastern France and southern Spain.

It forms a compact mound up to 30 cm in height.

Dense spiny branches of tiny, toothed grey-green leaves bear racemes of white flowers at the tips in early summer.

[1] It is especially cultivated in rock gardens.

The cultivar H spinosa 'Roseum',[2] with pink flowers, has gained the Royal Horticultural Society's Award of Garden Merit.