Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

Home to the plants of the Sonoran, Chihuahuan and Mojave Deserts

Cirsium ochrocentrum, Yellowspine Thistle

Cactaceae or Cactus Family

The Cactaceae or Cactus Family has several distinguishing characters the most well-known are the ever-present protective spines which are modified leaves developed to minimize water transpiration, cool the plant and provide protection from would-be predators. Although it's well documented that many animals have adapted strategies to which the spines provide no relief. Cactuses, or the generally accepted term, cacti, come in many forms, shapes and sizes many with beautiful forms and flowers, often pleasantly scented to attract localized pollinators, both vertebrates and insects as well.

Most cacti are succulents but not all succulents are cacti.

Almost all traditional cacti are native to the Americas and are specialized to thrive in areas with minimal rainfall and extremely dry conditions.

The Plant List recognizes 2,047 accepted species names in the family Cactaceae.

Some of the largest genera in the southwest include the following, although not all of the species are native to the southwest;

Mammillaria, 176 accepted species names
Opuntia, 161 accepted species names
Echinocereus, 62 accepted species names
Cylindropuntia, 43 accepted species names
Ferocactus, 26 accepted species names

References: Posted; 06/03/2015, updated, 09/15/2015
The Plant List. a working list of all plant species. [accessed June 03, 2015]
http://www.theplantlist.org/browse/A/Cactaceae/
Wikipedia contributors, 'Cactus', Wikipedia, The Free Encyclopedia, 18 May 2015, 23:21 UTC,
[accessed 3 June 2015]