The leaves have two whitish lines on the bottom, each of which is formed by wax-covered stomatal bands. In most species, the upper surface of the leaves is uniformly green and shiny, without stomata or with a few on the tip, visible as whitish spots. Other species have the upper surface of leaves dull, gray-green or bluish-gray to silvery (glaucous), coated by wax with variable number of stomatal bands, and not always continuous. An example species with shiny green leaves is "A. alba", and an example species with dull waxy leaves is "A. concolor".