The plant clearly divides into three major parts: firstly, the one that extends from the cotyledons to the calyx, the green part of the plant, that is, where the life principle is most active; secondly, the one comprising the flower itself with the organs of fertilization, where the vitality of the plant gives way to other principles; and lastly, the fruit and seed, which are destined to be discharged from the mother organism. Each of these three contains two kinds of organs: first, organs with the tendency to grow into width-leaf, flower and fruit; second, organs which are outwardly smaller and simpler, but have the function of preparing the decisive leaps in the plant's development: these are the calyx, the stamens, etc., and the seed. In this succession, Goethe recognized a certain rhythm of expansion and contraction, and he found that the plant passes through it three times during any one cycle of its life. In the foliage the plant expands, in the calyx it contracts; it expands again in the flower and contracts in the pistil and stamens; finally, it expands in the fruit and contracts in the seed. The deeper meaning of this threefold rhythm will become clear when we consider it against the background of what we observed in the metamorphosis of the leaf. Take the mallow leaf; its metamorphosis shows a step-wise progression from coarser to finer forms, whereby the characteristic plan of the leaf comes more and more into view, so that in the topmost leaf it reaches a certain stage of perfection. Now we observe that in the calyx this stage is not improved on, but that the plant recurs to a much simpler formation. Whilst in the case of the mallow the withdrawal from the stage of the leaf into that of the calyx occurs with a sudden leap, we observe that the delphinium performs this process by degrees. Whilst the mallow reaches the highly elaborate form of the leaf only in the final stage, the delphinium leaps forth at the outset, as it were, with the fully accomplished leaf, and then protracts its withdrawal into the calyx over a number of steps, so that this process can be watched with our very eyes. In this type of metamorphosis the last leaf beneath the calyx shows a form that differs little from that of a calyx itself, with its simple sepals. Only in its general geometrical arrangement does it still remind us of the original pattern. In a case like this, the stem-leaves, to use Goethe's expression, 'softly steal into the calyx stage'.4 In the topmost leaf the plant has already achieved something which, along the other line of metamorphosis, is tackled only after the leaf plan itself has been gradually executed. In this case the calyx stage, we may say, is attained at one leap.