The common dandelion, taraxacum officinale
, was introduced from Europe and has spread all across the US. The yellow flower heads, 1.5 inches in diameter, consist of between 40 and 100 narrow ray petals, forming a semi-sphere when fully in bloom. Petals have straight edges and a notch on the tip. Beneath the petals are green bracts, curling back towards the unbranched, hollow stem, which contains milky sap. The flowers are followed by thin, feathery seeds that angle in all directions to form a complete sphere. Leaves grow only around the base.