Bronze Mignonette Lettuce Seeds (Aimers International) Heirloom Vegetable. Variety originated in USA. This loose-leaf butterhead type is very slow to bolt to seed. Large open heads to 454 g (1 lb). Frilled green leaves have a bronze tinge with a cream coloured heart. Makes a crisp colourful addition to any salad. Good for small space gardens. Matures in 55 days.