To complete the statement it must be added that these variations of nutrition often determine the development or non-development of lateral axes; and by so doing cause still more marked structural differences. The Foxglove may be named as a plant which illustrates this truth.[40] § 240. From the morphological differentiations caused by unlikenesses of nutrition felt by the whole plant, we pass now to those which are thus caused in some of its parts and not in others. Among such are the contrasts between flowering axes, and the axes that bear leaves only. It has already been shown in § 78, that the belief expressed by Wolff in a direct connexion between fructification and innutrition, is justified inductively by many facts of many kinds. Deductively too, in § 79, we saw reason to conclude that such a relation would be established by survival of the fittest; seeing that it would profit a species for its members to begin sending off migrating germs from the ends of those axes which innutrition prevented from further agamogenetic multiplication. Once more, when considering the nature of the phænogamic axis, we found support for this belief in the fact that the components of a flower exhibit a reversion to that type from which the phænogamic type has probably arisen--a reversion which the laws of embryology would lead us to look for where innutrition had arrested development. Hence, then, we may properly count those deviations of structure which constitute inflorescence, as among the morphological differentiations produced by local innutrition. I do not mean that the detailed modifications which the essential and subservient organs of fructification display, are thus accounted for: we have seen reason to think them otherwise caused. But I mean that the morphological characters which distinguish gamogenetic axes in general from agamogenetic axes, such as non-development of the internodes and dwarfing of the foliar organs, are primarily results of failure in the supply of some material required for further growth.[41]