WildBristol.uk - Discovering Wildlife in Bristol

Found on a bike shed green roof along with other colonised plants but doesn't appear to have been intentionally planted. It was probably introduced with the substrates. Almost looks intermediate between Capsella and Erophila.

Plant tiny c. 4 cm tall; basal leaves ovate-elliptic, inconspicuously dentate, petiolate, covered in stellate hairs and sparse simple hairs on margin. Stem brownish, covered in stellate hairs; Stem-leaves alternating, 3-4, narrowly ob-elliptic, c. 3 mm long, inconspicuously dentate, covered in stellate hairs and simple hairs on margin; flowers 3 per stem, pendent to one side; sepals green with magenta margins, sparsely hairy, c. 1 mm; petals obovate, clawed, c. 2.5 mm, double the length of the sepals; capsules ob-triangular and Capsella-like, c. 2 x 2 mm, convex-sided with a slight notch and protruding style.