The look of a cactus can be quite deceiving. Spiny, leafless desert cacti, mostly native to North and South America, transform into some of the most dazzling plants when in bloom. Belonging to the Cactaceae plant family, more than 1,000 different species of cacti exist, including those of the tropical variety that are indigenous to Brazil.

...
Cactus flowers bloom in a rainbow of colors.

Desert Cultivars

Following a period of about five years, bright yellow blossoms with red throats -- the flowers' tubular organs -- appear on small sea urchin cacti (A. asterias). Compass barrel cacti (F. cylindraceus) boast bell-shaped, orange and yellow flowers. Buds on the Claret Cup Hedgehog (E. triglochidiatus) burst open into vivid scarlet hues. The Rose Pincushion cactus (M. zeilmanniana) produces reddish-violet blossoms and, on the small, Snowball Pincushion variety (M. candida), rings of cream-colored flowers turn to pink.

Tropical Holiday Cacti

...
Christmas cacti bloom on the stem tips.

Blooming in white and a multitude of colors including red, lavender, orange, pink and yellow, Thanksgiving and Christmas cacti (S. truncata and S. bridgesii), as well as the Easter cactus (R. gaertneri), create showy holiday displays. These tropical cacti bloom in abundance and sport wide, flat, leaf-like stems. Thanksgiving cacti flower through the holiday and well into January. Christmas cactus blossoms open on the stem tips and bloom for long periods in cooler temperatures. Blooming mainly in spring, Easter cacti may flower at other times during the year.

Night-blooming Cacti

Cactus flowers grow from the area of the plant known as the cephalium. Column cacti (C. uruguayanus) bloom at night in white with petal tips of diverse colors. The night-flowering orchid cactus of the Epiphyllum species produces blossoms in multiple hues during late summer and early autumn. The sweetly scented flowers of the orchid cactus can reach a length of 6 inches or more.

Pollination

...
In daytime, brightly colored cactus blossoms attract bees and hummingbirds.

The brilliant hues of cactus blossoms attract daytime pollinators such as bees and hummingbirds. Dim light reflecting from the soft colors of night-blooming cacti, along with the plants' heady scent, draw moths and bats for pollination. In southwestern North America's Sonoran Desert, the fragrant blossoms of saguaro (C. gigantea) and organ pipe cacti (S. thurberi) lure bats to their sweet nectar. The bats emerge from their nectar feast covered in pollen, contributing to the pollination process as they fly from flower to flower.