Sunflowers belong to the genus Helianthus, which consists of many species. The common sunflower, the crop grown for its edible oil, is the Helianthus annuus.
This species is also used as food for livestock as well as for ornamental purposes in domestic gardens. Sunflower plants are usually tall, reaching over 9 feet in height. The tallest ever recorded sunflower measured over 30 feet in height.
Besides oil, sunflower seeds are also harvested and sold as a popular snack. Interestingly, sunflowers are also good for the environment – these plants can pull radioactive particles and heavy metals from the environment. Based on this idea, researchers in Japan are planting fields of sunflowers around the Fukushima area, in the hopes of cleaning up radioactive waste from the soil.