Southwest Colorado Wildflowers, Cactaceae

Cactus are as evocative of the West as Sagebrush; the two even often grow near each other. Cactus are indigenous to the Western Hemisphere, are found in their greatest concentration along the Tropics of Cancer and Capricorn, and are native to every American state except Vermont and Maine. They are found in deserts, on seashores, in mountains, on plains, balds, and glades.

Cactus come in a number of shapes, their flowers are often very large and attractive, their fruits are edible (some delicious, some not so), and they have evolved a number of structures and processes that make them perfectly at home in what we humans usually call "a hostile environment": They have a tough, waxy outer layer that reduces moisture loss; they produce chlorophyll not in leaves but in the outer cells of the stems; they convert absorbed water into a mucilaginous liquid that can be stored in large quantities in tissues capable of expanding; many Cactus root easily into new plants from broken pads/stems of older plants.

"Cactus" is Greek for "prickly plant"; the word was used by Linnaeus in the 18th century to describe a prickly, thistle-like member of the Asteraceae Family found in Italy. "Cactus" was then used in the 19th century for the newly discovered spiny, drought resistant plants discovered in the Western Hemisphere.

Since flower color in both Opuntia phaeacantha and Opuntia polyacantha ranges from shades of yellow to copper-yellow to pink to magenta, flower color cannot be used to distinguish between the two species. The spines and glochids of the fruit, seed texture, spine shape, and spine spacing are key distinguishing characteristics.

Lower pads of a number of Cacti (including Opuntia polyacantha and Opuntia phaeacantha) often sprawl on the ground, soil accumulates on the uphill side of the pads, and they are often buried. New pads grow on the higher soil level.

The name "Opuntia" was used by Theophrastus for a plant, not in the Cactus Family, which grew near the Greek town of Opus. Somehow "Opuntia" was centuries later applied to this genus of Cacti.

Opuntia phaeacantha (Prickly Pear Cactus)
Cactaceae (Cactus Family)

Semi-desert, foothills. Openings. Spring, summer.
Canyons of the Ancients National Monument, May 24, 2004.
Navajo Reservation, Blackrock Canyon, New Mexico, June 9, 2001.

There are a number of varieties of Opuntia phaeacantha; all commonly grow three to five feet tall and wide, but in the Four Corners area they are most commonly ground hugging and sprawling. Opuntia phaeacantha has pads that range from three to ten inches, spines that are widely spaced and brown-tipped, and, most often, yellow flower petals with red-to-orange tinting at the base. Flowers can also be magnificent shades of pink.

The second Opuntia phaeacantha pictured at left is experiencing drought conditions as evidenced by its wrinkled pads.

It is common to find Opuntia phaeacantha pads that have semi-circular chunks missing from them -- the work of deer. The smaller nibbles are taken by squirrels, chipmunks, and mice and the missing fruit has often disappeared into collecting bags of humans who relish it for pies, jams, and muffins.

"Phaeacantha" is Greek for "dusky thorn" referring to the brown-tipped spines.

Click for more Opuntia phaeacantha photographs.

Opuntia polyacantha (Prickly Pear Cactus)
Cactaceae (Cactus Family)

Semi-desert, foothills. Openings. Spring, summer.
Hidden Valley Trail, Utah, May 10, 2007.

Opuntia polyacantha plants are low and sprawling with pads two to six inches wide and long. Spines grow close together with many arising from the same point. ("Polyacantha" is Greek for "many thorns".) Flowers, ranging from yellow to hot pink (see below), are very large in relation to the pad size. New pads (on the right, center, and left side of the picture) are soft, as are their short, undeveloped spines. The winter of 2006-2007 produced ideal growing conditions for many plants, including these Cacti and you can see how much larger the new growth is. Pads will probably round out as they mature. The ideal conditions favored bud and flower growth as well as pad growth. There are nine buds ready to open.

Opuntia polyacantha hybridizes readily and the Flora of North America now lists a number of varieties. An entire former Opuntia species, O. erinacea is now broken into a number of varieties of O. polyacantha.

Click for more O. polyacantha.