This plant, Coprosma acerosa, is found scrambling through shifting sands. Its small leaves and tough stems are ideally adapted to the dry, sand dune habitat in which it exists. The small leaves produce a smaller surface for water loss, and the tough stems are thickened to reduce water loss.
This plant is called leafless broom, or Carmichaelia aligera. It has adapted to dry areas by reducing its leaves so that they do not exist. Leaves would have provided a large surface for water loss; with out leaves water loss is reduced. It has made its stem photosynthetic, to replace the role that the leaves would have had. Thus glucose is made in the green stem of this plant, through the process of photosynthesis.