1115. The spiriform arrangement stands in relation with the formation of the tracheæ. 1116. The branches of the root observe no such regularity, partly on account of weaker polarity, partly on account of the obstacles placed in their way, at one time by the impenetrable earth, at another by want of water. 1117. The more the stem is differenced, so much the higher is it developed. Thus the richer in number the branches, by so much the more perfect is the stem. The stelliform branches belong to the first development. The plants, that have this arrangement, stand lower in the scale. To this the crucial appears to succeed, as a mediate position between the former and that which follows. The spiriform ranks higher. In it the stem is manifestly differenced more multilaterally. The dispersed arrangement appears to be the highest, because in it the greatest freedom prevails, because the poles have acted on every part of the plant, because they are everywhere in the air and in light. Plants with dispersed branches are organized air; without branches they are organized water as well as earth. Those plants only which have circles of tracheæ or rings of wood, as e. g. the Dicotyledons, ramify; these alone are, properly speaking, a conjunction by growth of many plants, and one that is truly persistent, or that bears fruit several times. The Monocotyledons being devoid of woody rings, do not, or but very rarely, ramify. Most of them therefore die off after they have once produced fruit. The ramification is a multiplication of the plant, in which the buds continue to stand upon the old stem. _Formation of Nodes._ 1118. The formation of nodes, as in the grasses, is an attempt at differentialization, that has not, however, attained to perfection. A node is a branch-whorl which has continued to adhere to the stalk. Therefore the tracheæ also terminate in the circumference of the node. 1119. The formation of nodes consequently ranks directly under the stelliform formation of branches. Taken in a strict sense the formation of nodes occurs only in plants with sheathing leaves or in Monocotyledons. 3. AIR-ORGAN, FOLIAGE. 1120. If in the progressive separation of the tissues the tracheæ finally obtain the preponderance, so that they issue forth free from the envelope of cellular tissue, the _leaves_, or _Foliage_, then originate. 1121. The ribs of the leaf are the fascicles of tracheæ that have become free, and are still only connected together laterally by a thin layer of cellular tissue. 1122. The leaves can be regarded as gigantic and unrolled spiral vessels, and these again as microscopic and involuted leaves. 1123. As through the root the water-process enters the plant, and through the stalk the earth-process, so does the air-process through the leaves. 1124. It is probably the stomata through which the air is conducted into the tracheæ; the connexion, however, has not yet been proved. _Gemmæ or Buds._