In fact the envelopes of the flower and the cotyledons approach so nearly to the character of leaves, that every unprejudiced eye must instinctively perceive the resemblance; and if doubts arose on this point in post-Linnaean times, it was only a consequence of the Linnaean terminology, which neglected all comparative examination. Moreover the doctrine of metamorphosis appears in a more consistent and necessary form in Cesalpino than in the botanists of the 19th century before Darwin; it flows more immediately from his philosophical views on the nature of plants, and appears therefore up to a certain point thoroughly intelligible. We may also consider as part of this doctrine in Cesalpino the view that the substance of the seed (embryo and endosperm) arises from the pith, because the pith contains the vital principle[18], and as the pith in the shoot is surrounded for protection by the wood and the bark, so the substance of the seed is surrounded by the woody shell, and by the bark-like pericarp or by a fruit-envelope answering to a pericarp. According to Cesalpino therefore the substance of the seed with its capability of development springs from the pith, the woody shell from the wood, the pericarp from the rind of the shoot. The difficulty which arises from this interpretation, namely, that in accordance with his theory the parts of the flower also, the calyx, the corolla, and the stamens ought to spring from the outer tissues of the shoot, he puts aside with the remark (p. 19) that these parts of the flower are formed when the pericarp is still in a rudimentary state; that the pericarp is only fully developed after these parts have fallen off, and that they are so thin that there is nothing surprising in this view of the matter. We see in Cesalpino’s doctrine of metamorphosis without doubt the theory of the flower afterwards adopted by Linnaeus, though in a somewhat different form. That Linnaeus himself regarded the theory ascribed to him on the nature of the flower as the opinion of Cesalpino also, is shown in his ‘Classes Plantarum,’ where in describing Cesalpino’s system he says: ‘He regarded the flower as the interior portions of the plant, which emerge from the bursting rind; the calyx as a thicker portion of the rind of the shoot; the corolla as an inner and thinner rind; the stamens as the interior fibres of the wood, and the pistil as the pith of the plant.’ It may be observed however that this was not exactly what Cesalpino says; but it is nevertheless certain that Linnaeus’ own view as given in these words was intended to reproduce that of Cesalpino; and if it does not do this exactly, there is no essential difference in principle between the two, Linnaeus’ conception being perhaps a more logical statement of Cesalpino’s meaning. Cesalpino’s doctrine of metamorphosis appears plainly on another occasion also; he says, that we do not find envelopes, stamens, and styles in all flowers; the flowers change in some cases into another