ABSTRACT
Convergent evolution results when unrelated organisms develop similar adaptations to similar environmental conditions. Desert plants survive long rainless periods with three main adaptive strategies: succulence, drought tolerance, and drought evasion. Drought tolerance or drought dormancy refers to desert plants' ability to withstand desiccation. Some plants in this adaptive group are notoriously difficult to cultivate, especially in containers. It seems paradoxical that desert ferns and creosote bushes, among most drought-tolerant of desert plants, can be kept alive in containers only if they're never allowed to dry out. Every time the desert has wet fall or winter, it will turn green with annuals, but not always ablaze with other colors. The tiny seeds are covered with a soluble fiber that forms a sticky mucilage when wet by rain; this aids germination by retaining water around the seed and sticking it to the soil. Small, brightly colored fruits such as hackberry and boxthorn are offered as food for birds that swallow them whole.
