Is it Cactuses or Cacti?
Whatever the answer, you’ll find a lot of them at the Desert Botanical Gardens in Papago Park. The 140 acre botanical park was established at this site in 1939 by the Arizonza Cactus and Native Flora Society. The garden has more than 21,000 plants many of which are rare, endangered or threatened. Cactus describes a single plant and the plural is “cacti”.
Collection of desert plants
The collection of cacti is a reminder of the diversity of plants that are native to the valley. The saguaro is probably the most familiar and notable cactus, but you’ll quickly become acquainted with others such as the organ pipe, barrel cactus, cholla, ocotillo, prickly-pear, etc.
Several different desert environments are represented in the garden with the native vegetation. Because 169 species at the garden are rare and endangered, it serves an important conservation purpose.
Even long time Phoenicians will learn something about the desert that they might not have known. 
For example, I have always thought that the number of arms on a saguaro cactus was an indication of the age of the plant. A display explained that a saguaro begins to grow arms when it is 50 – 100 years old, and may grow many arms at once. Most saguaros live 200 years, some can live up to 300 years. Another interesting fact is that a large saguaro cactus can store up to 1,500 gallons of water, enough to last months or years. A saguaro can soak up hundreds of gallons of water after a single rainfall. 
The moisture storing pulp resembles the inside of a cucumber.
There are many more pictures in the link below.
More pictures of the Desert Botanical Garden in Papago Park
My wife and I pretty much had the park to ourselves which is understandable when it is 103 degrees outside. In another 4 weeks it will be a much more enjoyable adventure. The cost for an adult is $15. If you’ve been to the park, 
leave a comment on your experience.
