Umbels of yellow flowers with unequal rays. Flattened seeds, winged edges.
Pinnate leaves with toothed, lobed segments. Stems hollow, furrowed,
branched. Sap causes blisters due to severe sensitivity to sunlight.
Hairy, strong-smelling plant. Height: 60-120cm.
Found on dry sandy soils, waste ground, roadsides, rough grassland. Infrequent casual, but can be persistent.