Plants 30 cm tall. Stems 10-20 mm thick, 4-angled, with wavy, crenate, rounded angles. Flowers from terminal, many-flowered umbels. Corolla yellow, densely covered with dark brown spots, often uniformly dark red-brown, 10-15 mm wide, tubular, the tube about 10 mm long, the lobes deltoid, ascending or recurved, with a tuft of short, purple vibratile hairs at their tips.