Big Beautiful Cactus. Ethel M Botanical Garden, Las Vegas
Most people who do not live in a desert environment consider cactus to be an unattractive species. Nothing could be farther from the truth, cactus are a beautiful species, similar to euphorbia in Africa. Euphorbia can be found all over the world. The forms range from annual plants laying on the ground, to well developed tall trees. In deserts in Madagascar and southern Africa, convergent evolution has led to cactus-like forms where the plants occupy the same ecological niche as cacti do in deserts of North America and South America. The genus is primarily found in the tropical and subtropical regions of Africa and the Americas, but also in temperate zones worldwide. The 1,500 to 1,800 species of cacti mostly fall into one of two groups of “core cacti”: opuntias (subfamily Opuntioideae) and “cactoids” (subfamily Cactoideae). Most members of these two groups are easily recognizable as cacti. They have fleshy succulent stems that are major organs of photosynthesis. They have absent, small, or transient leaves. They have flowers with ovaries that lie below the sepals and petals, often deeply sunken into a fleshy receptacle (the part of the stem from which the flower parts grow). All cacti have areoles highly specialized short shoots with extremely short internodes that produce spines, normal shoots, and flowers. In Las Vegas we have one of the best cactus gardens in the world at the Ethel M Botanic Garden.