Iyengar

Iyengar is a style of yoga which is based on classical yoga postures and evolves from the same roots as ashtanga yoga.  It therefore encompasses postures from ashtanga yoga: the difference being that one practices the postures individually with great attention being paid to alignment. 
Iyengar yoga is excellent in itself for conditioning, toning and improving flexibility, as well as for enhancing one's ashtanga or flow yoga practice.