Bitter Vetch is a perennial of the pea family; it is sometimes called Heath Pea. The flowers are a rosy purple; the narrow leaflets grow in pairs. It is remarkable that Bitter Vetch, unlike most other peas and vetches, has no tendrils.
This is a common plant on acid soil, at the edge of woods and in scrubland. It grows in many districts of Ireland, but is not found in Meath or Longford; it is easily found by the lower Lake of Killarney.
The flowers are in bloom from May to July.
Bitter Vetch grows in Britain, except for East Anglia, and in much of western and central Europe.