The Asian varieties of basil are Thai basil and holy basil. Both have green leaves with a purple underside and tips and purple flowers. Holy basil has bigger leaves than Thai basil. Both have an aniseed fragrance and flavour.
Choose fresh looking basil with unmarked leaves. Avoid blackened, wilted leaves. Store in a plastic bag in the refrigerator for a few days. Sweet basil, Thai basil and holy basil are available all year round. Green basil is available in the summer months.