It's not fennel, and doesn't resemble any parsley I'm familiar with. This may be a different type/variety of the type of cilantro that is grown in stores. When an annual herb such as cilantro flowers, it is beginning the end of its life cycle. The flowers turn to seeds, and the plant itself dies. Cilantro is notorious for what's called "bolting", or early flowering, especially in hot weather. I do see some of the more typical cilantro leaves in the picture, the bigger leaves. Best thing to do is to regrow from seed. It's often recommended that if it is grown for the leaves to make successive plantings from spring through fall.