Araxacum officinale is a medical herb of the family Asteraceae (Compositae). It can be found worldwide in flatlands of temperate regions.
It is considered throughout the world to be a weed, and is also known as the common dandelion. Dandelions are plants, native to temperate areas of the Northern Hemisphere of the Old World. They are commonly known as weeds.
The leaves are 5-25 cm long, simple and basal, entire or lobed, forming a rosette above the central taproot. As the leaves grow outward they push down the surrounding vegetation, such as grass in a lawn, which kills other plants by cutting off their access to sunlight. A bright yellow flower head which is open in the daytime but closes at night is borne singly on a hollow stem which rises 4-30 cm above the leaves and exudes a milky sap (latex) when broken. A rosette may produce several flowering stems at a time. The flower head is 2-5 cm in diameter and consists entirely of ray florets.(Wikipedia.org)