marigold or saffron
Dried, ground petals of the marigold (Tagetes), known in Georgia as Imeretian saffron; it colours food golden yellow and tastes earthy, floral and slightly bitter.
Imeretian saffron is not saffron at all but the orange-yellow powder of dried marigold (Tagetes) petals; it is sometimes confused with calendula, or pot marigold. It tastes gently earthy, floral and slightly bitter, and its main job is colour, without the honeyed, intense aroma of true saffron. In Georgian cooking it goes into walnut sauces, vegetable and walnut pastes, stews and the spice blend khmeli suneli. Look for it in Georgian, Russian or Eastern European grocers, occasionally in Turkish supermarkets, and from mail-order spice sellers. True saffron threads are sold in well-stocked supermarkets, spice shops and some pharmacies, at a much higher price.
Substitute:
A pinch of true saffron soaked in a little warm water gives the same colour but a stronger, sweetish floral aroma, so use it sparingly. A small amount of turmeric colours similarly but is earthier and sharper and should not become noticeable. Dried calendula petals from herbal shops colour more weakly and taste milder. None of them quite matches the particular note of marigold, though in walnut sauces the difference is slight.