Tropical alpine environments (at altitudes above the closed canopy forest and below the limit of plant life) present an unusual set of complex stresses for plant species. Unlike temperate alpine environments, where there are distinct seasons of favorable and unfavorable conditions for growth, tropical alpine habitats present summer conditions every day and winter conditions every night. As a consequence, tropical alpine plant species have evolved unique forms for coping with such a hostile environment. Using examples from all over the tropics, this fascinating account reviews the unique form and functional relationships of tropical alpine plants, examining both their physiological ecology and population biology.