This is a wildflower called a weed. If you have a lawn to care for, you may have called it several other names as it is probably the most stubborn weed of all. You can cut it off at the ground but unless you dig out the entire root, the dandelion will come up stronger than ever.
At the top of the root, at ground level is a rosette of deeply notched leaves, which do a good job of shading or choking out other plants, such as grass. Rising from the center of the plant are one or more hollow stalks, each supporting a blossom. This blossom is really a tight cluster of many flowers. Each bright yellow petal is actually a complete flower in itself, able to form a seed.
A few weeks after blooming, each little floret sends up a white, threadlike, silky stalk. These form the familiar puff-balls so easily dispersed by the wind. At the bottom of each fluffy stalk is a dandelion seed. It has tiny barbs, or hooks, that help it get a firm hold wherever it happens to land.
The dandelion has a long and interesting history as a medicinal plant and as foodstuff. Its young sprouts have been valued as a pot-herb, its fresh leaves enjoyed as a salad, and its dried roots used as a substitute for coffee in various countries and ages.
