The Cupboard
Thai Basil
Thai basil, or Asian basil (húng quế in Vietnamese) is a type of sweet basil native to Southeast Asia that has been cultivated to provide distinctive traits. Its flavor is more stable under high or extended cooking temperatures than that of sweet basil. Thai basil exhibits small, narrow leaves and purple stems, with a mauve (pink-purple) flower. One cultivar commonly grown in the United States is 'Queen of Siam'.
Sweet basil, Ocimum basilicum (O. basilicum), has multiple cultivars. Thai basil, or O. basilicum 'Horapha', grows to 45 cm (1.48 ft in height, and has purple-flushed, lance-like leaves with a sweet licorice scent.
The word Ocimum is derived from the Greek word meaning "to smell" which is appropriate for most members of the plant family Lamiaceae, also known as the mint family. Like other plants in the mint family, Thai basil features a square stem, and the leaves always grow in pairs, opposite each other and at 90 degree angles from the previous pair of leaves. With over 40 cultivars of basil, this abundance of flavors, aromas and colors leads to confusion when identifying specific cultivars.
Although Vietnamese, Cambodians, and Laotians also use the Asian varieties of basil in their cuisines, the purple-stemmed, licorice-flavored leaves have come to be identified as Thai basil. It may be mistakenly called anise basil or licorice basil, but it is different from the Western strains bearing these same names. The leaves of the horapha variety are a frequent ingredient in Thai green and red curry, while the basil used in Thai drunken noodles, and Thai chicken/pork/seafood with basil leaf is kraphao (Thai holy basil). Thai basil is also an important ingredient in the very popular Taiwanese dish, sanbeiji (three cup chicken). Used as a condiment, a plate of raw Thai basil leaves is often served as an accompaniment to phở (Vietnamese-style noodle soup) so each customer can season it to taste with the anise-flavored leaves. —Resource Wikipedia
Note: Thai basil adds particularly good flavor to fried rice.