Ranunculus (Ranunculus sp.).
Ranunculus belong to the Buttercup family (Ranunculaceae). They are native to the Middle East, hence their alternative name "Turban Buttercup". Ranunculus has tuberous roots and hollow stems, and a wonderful array of colors, yellow, white, red, pink, orange, and and copper, either peony flowered or open flowered, with dark or yellow centers. For more pictures of Ranunculus, please visit The Flower Fields at Carlsbad, California.
If you want more information about this flower, just search the plant's Latin (botanical) name on Google: