To become more familiar with the conception of the ur-plant, let us bring the life-cycle of the plant before our inner eye once again. There, all the different organs of the plant-leaf, blossom, fruit, etc. - appear as the metamorphic revelations of the one, identical active principle, a principle which gradually manifests itself to us by way of successive heightening from the cotyledons to the perfected glory of the flower. Amongst all the forms which thus appear in turn, that of the leaf has a special place; for the leaf is that organ of the plant in which the ground-plan of all plant existence comes most immediately to expression. Not only do all the different leaf forms arise, through endless changing, out of each other, but the leaf, in accordance with the same principle, also changes itself into all the other organs which the plant produces in the course of its growth. It is by precisely the same principle that the ur-plant reveals itself in the plant kingdom as a whole. Just as in the single plant organism the different parts are a graduated revelation of the ur-plant, so are the single kinds and species within the total plant world. As we let our glance range over all its ranks and stages (from the single-celled, almost formless alga to the rose and beyond to the tree), we are following, step by step, the revelation of the ur-plant. Barely hinting at itself in the lowest vegetable species, it comes in the next higher stages into ever clearer view, finally streaming forth in full glory in the magnificence of the manifold blossoming plants. Then, as its highest creation, it brings forth the tree, which, itself a veritable miniature earth, becomes the basis for innumerable single plant growths. It has struck biologists of Goethe's own and later times that contrary to their method he did not build up his study of the plant by starting with its lowest form, and so the reproach has been levelled against him of having unduly neglected the latter. Because of this, the views he had come to were regarded as scientifically unfounded. Goethe's note-books prove that there is no justification for such a reproach. He was in actual fact deeply interested in the lower plants, but he realized that they could not contribute anything fundamental to the spiritual image of the plant as such which he was seeking to attain. To understand the plant he found himself obliged to pay special attention to examples in which it came to its most perfect expression. For what was hidden in the alga was made manifest in the rose. To demand of Goethe that in accordance with ordinary science he should have explained nature 'from below upwards' is to misunderstand the methodological basis of all his investigations.