St. Anthony the Great ca. 251-356
Because some people impiously dare to say that plants and vegetables have a soul, I will write briefly about this for the guidance of the simple. Plants have a natural life, but they do not have a soul. Man is called an intelligent animal because he has intellect and is capable of acquiring knowledge. The other animals and the birds can make sounds because they possess breath and soul. All things that are subject to growth and decline are alive; but the fact that they live and grow does not necessarily mean that they all have souls. There are four categories of living beings. The first are immortal and have souls, such as angels. The second have intellect, soul and breath, such as men. The third have breath and soul, such as animals. The fourth have only life, such as plants. The life of plants is without soul, breath, intellect or immortality. These four attributes, on the other hand, presuppose the possession of life. Every human soul is in continual movement. (On the Character of men and On the Virtuous Life)