The betel quid is chewed by a very large number of people across South Asia, Southeast Asia, Melanesia and Micronesia, and it is probably the most widely used ritual plant in Asia. It is almost always left out of accounts of sacred plants, on the grounds of being too ordinary.
The quid combines the nut of the areca palm, Areca catechu, with slaked lime, wrapped in a leaf of the unrelated betel pepper, Piper betle, often with other spices. The lime is essential chemistry rather than flavour: it frees the alkaloids so they can be absorbed. The effect is a mild stimulant warmth, and the practice stains the mouth red.
Its ritual use is extensive. Areca nuts and betel leaves are standard items of puja offering in Hindu practice, presented to deities and given to guests and priests; in Balinese Hinduism they appear in daily offerings; in Vietnamese and Malay tradition betel and areca are the formal gift of betrothal and marriage, to the point that the phrase for a wedding invokes them; and across the Austronesian world they figure in agreements, greetings and funerals.
The archaeology reaches back a long way. Betel-stained teeth and areca remains appear in burials in Southeast Asia and the Pacific across several thousand years, which makes it one of the oldest continuously used ritual plants anywhere.