Biology 1st Edition by Jerome Krueger, Kendra Hill, Robert Noyd

Exercise 18

The century plant, or agave, is an evergreen plant commonly used as an ornamental in the dry, hot regions of the southwestern United States ( Fig. ). Its leaves have a thick, waxy covering, which gives them a bluish-gray color. Agaves lose very little water through transpiration, and if you were to look at their stomata with a magnifying glass, you would see they were closed during daylight hours. How does this provide a competitive advantage to the agave? How does it limit water loss?
Figure Thick, waxy leaves of the Agave, or century plant.