Many people use the words “spice” and “herbs” interchangeably; however, there is a difference. Spices grow in tropical areas and come from the bark, buds, fruit, roots, seeds or stems of plants and trees. They are usually dried, though garlic and ginger root are exceptions. Herbs grow in temperate climates and are the fragrant leaves of plants. Sometimes, even the seeds of herbs are used in cooking; for example, coriander seeds are used in curry powder, while the leaves are cilantro (used in Mexican dishes).
Guide to Herbs and Spices