Cultivars of the sweet potato have been bred to bear tubers with flesh and skin of various colors. Sweet potato is only distantly related to the common potato, both being in the order Solanales.
Some researchers, citing divergence time estimates, suggest that sweet potatoes might have been present in Polynesia thousands of years before humans arrived there. However, the present scholarly consensus favours the pre-Columbian contact model.
The flowers open before sunrise and stay open for a few hours. They close again in the morning and begin to wither. The edible tuberous root is long and tapered, with a smooth skin whose color ranges between:
Its flesh ranges from beige through white, red, pink, violet, yellow, orange, and purple. Sweet potato cultivars with white or pale yellow flesh are less sweet and moist than those with red, pink or orange flesh.
Comparison to other food staples
With care, early-maturing cultivars can be grown as an annual summer crop in temperate areas, such as the Eastern United States and China. Sweet potatoes rarely flower when the daylight is longer than 11 hours, as is normal outside of the tropics.
The starchy tuberous roots of the sweet potato are by far the most important product of the plant, although the leaves and shoots are also edible. In some tropical areas, they are a staple food crop.
Depending on the cultivar and conditions, tuberous roots mature in two to nine months. A nutritious juice drink is made from the orange-fleshed cultivars, and deep-fried snacks are also included.