Hutchinsia

Hornungia petraea, the hutchinsia or rock hutchinsia, is a tiny ephemeral annual herb in the family Brassicaceae native to western and central Europe, the Mediterranean basin, and parts of north Africa and western Asia, where it grows in shallow soil pockets over limestone, in old quarries, on bare rocky calcareous ground, in coastal dune turf, and on open chalk grassland. The plant is short-lived and germinates with autumn rains, flowers in early spring, and dies back by early summer. Plants are slender, glabrous, and only 3-15 cm tall, with much-branched wiry stems arising from a small basal rosette. The basal rosette leaves are pinnate, 1-3 cm long, with 3-9 small oblong entire leaflets; stem leaves are similar but smaller and reduced upwards. The inflorescence is a slender raceme of very small flowers, each less than 2 mm across, with four minute white petals only slightly exceeding the four green sepals. The fruit is a tiny flattened oval silicle 2-3 mm long, slightly notched at the apex, with two single-seeded valves separated by a narrow septum, characteristic of the Brassicaceae. Seeds are minute, pale brown, and dispersed when the fruit splits.