The genus Arenaria, known also as Irish Moss, or less attractively Sandwort, consists of plants that are usually mats or tight cushions of tiny leaves, with short-stemmed starry flowers, usually white. They make excellent rock garden plants.

Arenaria purpurascens makes mats or low cushions of deep green, narrow leaves, well covered with lots of bright but pale pinky-purple, starry flowers.