Note 34 — Chapter IX · THE SHAPES OF LEAVES.

We may note that some of these leaves, as those of the Lime, furnish indications of the ratio which exists between the effects of individual circumstances and those of typical tendencies. On the one hand, the leaves borne by these drooping branches of the Lime are with hardly an exception unsymmetrical more or less decidedly, even in positions where the causes of unsymmetry are not in action: a fact showing us the repetition of the type irrespective of the conditions. On the other hand, the degree of deviation from symmetry is extremely variable, even on the same shoot: a fact proving that the circumstances of the individual leaf are influential in modifying its form. But the most striking evidence of this direct modification is afforded by the suckers of the Lime. Growing, as these do, in approximately upright attitudes, the leaves they bear do not stand to one another in the way above described, and the causes of unsymmetry are not in action; and here, though there is a general leaning to the unsymmetrical form, a large proportion of the leaves become quite symmetrical.