Erysimum cheiri - Wallflower - (Brassicaceae)

Originally imported from the Mediterranean, Wallflowers are often seen on cliffs, especially in chalky or limestone areas.

Wallflowers

Wallflowers are members of the cabbage family; they have flowers with four petals. (Cruciferae was used as their family name, because the petals are well spaced and make a clearly visible cross; nowadays they are referred to as members of the family Brassicaceae.)