Vinyasa, also called flow because of the smooth way that the poses run together, and can incorporate many types of yoga, including Ashtanga and Power yoga
Flow classes string poses together to make a sequence. The sequence may be fixed, as in Ashtanga or Rocket yoga, in which the poses are always done in the same order, but most of the time vinyasa teachers have the discretion to arrange the progression of poses in their own ways.
In vinyasa yoga, each movement is synchronized to a breath. The breath is the primary focus, acting as an anchor as you move from one pose to the next.
Vinyasa allows for a lot of variety in poses. Expect to move, sometimes vigorously, from pose to pose. Whether the class is fast or slow, includes advanced poses or is very alignment-oriented, will depend on the individual teacher and the particular style in which he or she is trained.
Some classes include some warm-up stretches at the beginning while others launch straight into standing poses, and may utilize of aspects of several different traditions. Expect to go through any combination and variation of poses.