The so called sunflower belongs to the species Helianthus which is a genus of plants comprising about 70 species. All Helianthus species are native to North America and Central America except for three species in South America. The sunflower typically refers to the popular annual species Helianthus annuus whose round flower heads in combination with the ligules resembles the sun. These flowers are cultivated in temperate regions and some tropical regions as food crops for cattle, humans, and poultry and also as ornamental plants. The species Helianthus annuus extensively grows during the summer and persists up to the early fall with its peak growth season being mid-summer. Sunflower species which are perennial are not commonly planted and grown in gardens due to their tendency to spread rapidly and become invasive. Helianthus verticillatus which is a kind of whorled sunflower was listed as an endangered species in 2014 when the U.S. Fish and Wildlife Service issued a final rule in order to protect it under the Endangered Species Act. The primary threats to the species are industrial forestry and pine plantations in Alabama, Tennessee and Georgia. They grow up to a height of 1.8 m or 6 ft tall and are primarily found in woodlands, adjacent to creeks and moist, prairie-like areas.
In this sub category you can download free PNG images: Sunflowers Nature. In this category "Sunflowers" we have 12 free PNG images with transparent background.