Most people say there is “consciousness” when they begin to think—when one doesn’t think one is not conscious. But plants are perfectly conscious and yet they do not think. They have very precise sensations which are the expression of a consciousness, but they do not think. Animals begin to think and their reactions are much more complex. But both plants and animals are conscious. One can be conscious of a sensation without having the least thought.
Ref: Questions and Answers 1950-51