A tufted plant making a handsome basal rosette of 5-8cm long spathulate leaves. Flowering stems 10-30cm tall producing an elegantly branched panicle of starry white flowers, petals 4mm long with two yellow patches at the base of the three upper ones. The calyx ages rusty-red, hence the specific name. Alaska and the Rocky Mountains, by mountain streams and in damp positions. Has been fairly widely cultivated and, given plenty of peat and grit in the compost and a cool position, has not proved too difficult. Needs abundant water during the growing season. Grows readily from seed. Attractive but with monocarpic tendencies.