Seen with Goethe's eyes, the plant kingdom as a whole appears to be a single mighty plant. In it the ur-plant, while pressing into appearance, is seen to observe the very rule which we have found governing its action in the single plant - that of repeated expansion and contraction.7 Taking the tree in the sense already indicated, as the state of highest expansion along the ur-plant's way of entering into spatial manifestation, we note that tree-formation occurs successively at four different levels - as fern-tree (also the extinct tree-form of the horsetail) among the cryptogams, as coniferous tree among the gymnosperms, as palm-tree among the monocotyledons, and lastly in the form of the manifold species of the leaf-trees at the highest level of the plant kingdom, the dicotyledons. All these levels have come successively into existence, as geological research has shown; the ur-plant achieved these various tree-formations successively, thus giving up again its state of expansion each time after having reached it at a particular level. From the concept of the ur-plant Goethe soon learned to develop another concept which was to express the spiritual principle working in a particular plant species, just as the ur-plant was the spiritual principle covering the plant kingdom as a whole. He called it the type. In the manifold types which are thus seen active in the plant world we meet offsprings, as it were, of the mother, the 'ur-plant', which in them assumes differentiated modes of action. The present part of our discussion may be concluded by the introduction of a concept which Goethe formed for the organ of cognition attained through contemplating nature in the state of becoming, as the plant had taught him to do. Let us look back once again on the way in which we first tried to build up the picture of leaf metamorphosis. There we made use, first of all, of exact sense-perceptions to which we applied the power of memory in its function as their keeper. We then endeavoured to transform within our mind the single memory pictures (leaf forms) into one another. By doing so we applied to them the activity of mobile fantasy. In this way we actually endowed, on the one hand, objective memory, which by nature is static, with the dynamic properties of fantasy, and, on the other hand, mobile fantasy, which by nature is subjective, with the objective character of memory. Now, for the new organ of cognition arising from the union of these two polar faculties of the soul, Goethe coined the significant expression, exact sensorial fantasy.8 In terms of our knowledge of man's psycho-physical make-up, acquired earlier, we can say that, just as the nervous system forms the basis for memory, and the blood the basis for fantasy, so the 'exact sensorial fantasy' is based on a newly created collaboration of the two. *