Good question. In this picture is the Cobra Plant (Darlingtonia) from California. It produces a complex pitcher plant with a snake-like hood, fangs, downward pointing hairs, etc. However, it doesn't produce a single digestive enzyme. Instead, it relies on bacteria to do the digestion. If one were to include any plant that receives nourishment from dead insects on/in it's leaves, the number of carnivorous plants would jump from 700 to well into the thousands.

This question is greatly debated among botanists.