National Macadamia Nut Day is observed worldwide every September 4, celebrating the culinary use of macadamia nuts. Although not true nuts botanically, macadamias are the seeds of trees from the genus Macadamia, which is indigenous to Australia. This day highlights the unique characteristics of macadamias, which are low in protein but high in fat, containing about 22% palmitoleic acid, an omega-7 monounsaturated fatty acid. People celebrate by indulging in salted or chocolate-covered macadamia nuts, or by baking treats such as macadamia nut cookies or muffins. Macadamia nuts are commonly used in various dishes, including pastries and fruit salads, and macadamia oil is popular for its flavor in cooking.