Popular Studies of California Wild Flowers 65 



Cactus (Cactaceae) 



By Roland Rice 



There are about thirty-seven species of the four tribes or 

 genera of the Cactus Family to be found in California, and they 

 are mostly confined to the desert areas of the southeastern part of 

 the State. This plant family, which has about a thousand members, 

 is native to North and South America, with the exception of a few 

 African species of Rhipsalis. While they are generally considered 

 to be desert plants, there are many kinds which grow in the moist 

 tropics and a few, such as the Rhipsalis, grow on trees like mistletoe, 

 and some kinds may be found as far north as Canada. 



The Cactus is one of the youngest and latest developments in 

 plant types and it is a splendid example of the way Mother Nature 

 enables her children to meet the requirements of different localities. 

 The stems are thickened into various shapes and contain the green 

 coloring matter, chlorophyll, in little cells under the skin ; for they 

 are mostly leafless plants. They are armed with every conceivable 

 kind of big and little spines or thorns to protect themselves from 

 animals, and the skin is thickened and has but few pores to prevent 

 the evaporation of moisture which the plant hoards within itself. 



In California the Cactus flourishes in common with the rest of 

 the Mexican element of plant types, growing in what is known as 

 the Sonoran life zone. This Sonoran zone comes up from the 

 Mexican deserts in two belts. The upper Sonoran zone comprises 

 our chaparral belt of the foothill regions and the lower zone com- 

 poses the desert regions of the south and extends up through the 

 low plains of the San Joaquin and Sacramento Valleys. 



It is in the short season of spring on the desert that the odd 

 forms of Cacti suddenly bear flowers of surprising beauty in varying 

 shades of white, pink, red, yellow, and sometimes tinged with 

 green. One plant, Opuntia ramosissima, which is seldom seen, has 

 a small brown flower, which is an unusual color for flora. Some 

 of these flowers open only during the day, others at night. They 

 have various arrangements with insects for cross pollenization, for 

 some depend upon night-flying moths, while others lure the honey 

 bees or are content with the attention of flies. 



There are many plants of the desert region which are popu- 

 larly known as Cactus, but have no relation to that family. The 

 requirements of the region have given them somewhat similar habits 

 of thickened, leaf-like stems protected with many sharp thorns. 

 Among these, the Agaves, akin to the Century Plants of our gar- 

 dens, may be found in three varieties on the desert. They are 

 members of the Amaryllis Family and are related to the lilies, as 

 also are the Yuccas and strange Joshua Trees. 



The curious forms of Cacti give to the Land of Little Rain an 

 appearance which is peculiarly fascinating. Their gorgeous color 

 display of large and showy blooms is enhanced perhaps by the lack 

 of foliage. This sudden flash of ephemeral beauty is but a promise 

 to the desert people of the rich harvest to come with the abundance 



