a part of a plant extended into length and breadth in such a manner as to have one side distinguishable from the other. This is Miller's definition. Linnaeus denominates leaves the organs of motion, or muscles of the plant. See Physiology, Vegetable.

Leaf-Skeletons. One help for acquiring a knowledge of the anatomy of plants, is the art of reducing leaves to skeletons, which may be done by exposing the leaves to decay for some time soaked in water, by which means the softer parts will be separated from the internal and harder. By carefully wiping, pressing, and rinsing them, the harder parts may be obtained from the rest quite entire. Some have been able to separate the outer covering on both sides from the woody net, and even to split the latter into two. A naturalist in the year 1645 first conceived the idea of making leaf-skeletons by employing decomposition for that purpose, assisting it by several ingenious operations of art. When the method of producing these skeletons was publicly known, numberless preparations of them were everywhere attempted. So much did leaf-skeletons afterwards engage the attention of philosophers, that one Seligmann wrote a treatise on the various methods which might be employed in their preparation.

clocks and watches, is an appellation given to the notches of their pinions.