Page:Forbes Watson - Flowers and Gardens.djvu/38

 Now all this the dot helps to accomplish. It emphasises just that point which should catch the eye at once, guiding it straight to the outlines or leading lines, and rescuing the whole plant from what might otherwise appear but a confused patch of green. This plan of leading the eye is continually adopted by painters. There is a good example of it in Leonardo da Vinci's "Last Supper," where the radiating beams of the roof and main lines of the bodies of the disciples converge towards the head of Christ, thus carrying us at once to the grand point of the picture. The means which are used in different kinds of leaves to make the outlines more noticeable are often well worth examining. Sometimes it is by thickening, as in the case we have already mentioned, sometimes by means exactly opposite. Very frequently, as in the Lily of the Valley, a thin line of cuticle surrounds the leaf, and gleams in the light by its transparency. In the common purple Iris of the gardens, where the leaf is like a broad sharp sword- blade, there is a gradual thinning from the centre towards the edges, as well as a translucent margin. So that, look at what distance you will, the large broad surfaces are easily distinguishable from