FIGURE 15.6 Adaptations. Desert plants have evolved several different adaptations to their desert environment. (a) The wedgeleaf draba (Draba cuneifolia) has leaf hairs that reduce water loss. (b) The Leuchtenbergia cactus (Leuchtenbergia principis) has a large taproot to draw water from deep in the soil. (c) The waxy outer layers of Aloe vera reduce water loss. (Inset) Close-up of waxy layer on an aloe that has been scraped with a knife.

(a: FPI/Alamy; b: Ian Nartowicz; c: Mark Hannaford/JWL/Aurora Photos; inset: Lee Wilcox)