When we talk about "plant teachers" we are talking about plants like Achuama o San Pedro, Ayahuasca, Peyote, Iboga, Tabaco, Coca and others.
Indigenous peoples, and specialist in the use of these plants, like shamans, consider them "teachers". For those who use these plants contain a "spirit", "charm", "power" or "virtue" able to transmit messages and teachings to those skilled in its ritual use. These plants are like teachers in a plant form that aperture awareness and a path of spiritual evolution.
There is a communication a "inter subjectivity" between the person-who takes a caring and respectful attitude, and the master plan is established. In conclusion, these plants are called "Masters" because they teach you something and they are sacred because they are connecting you with the source of life, cleaning your channels and opening your perception and consciousness, they show you a spiritual path and purpose that we have like spirits on this planet and life time.