Leaf margins

General characteristics

The shape and structure of leaves vary considerably from species to species of plant, depending largely on their adaptation to climate and available light, but also to other factors such as grazing animals, available nutrients, and ecological competition from other plants. Considerable changes in leaf type occur within species, too, for example as a plant matures (Eucalyptus species commonly have isobilateral, pendent leaves when mature and dominating their neighbors; however, such trees tend to have erect or horizontal dorsiventral leaves as seedlings, when their growth is limited by the available light.) Other factors include the need to balance water loss at high temperature and low humidity against the need to absorb CO₂. In most plants, leaves also are the primary organs responsible for transpiration and guttation (beads of fluid forming at leaf margins).