The Ubiquitous Palo Verde

OK so it isn't a Giant Sequoia Sequoiadendron giganteum but it is the State Tree of Arizona. There are three different species of palo verde native to Arizona, the Jerusalem thorn Parkinsonia aculeata ; the blue palo verde Parkinsonia florida (shown above) and the yellow palo verde Parkinsonia microphylla. The classification of the tree is as follows from the USDA:

Kingdom	Plantae – Plants
Subkingdom	Tracheobionta – Vascular plants
Superdivision	Spermatophyta – Seed plants
Division	Magnoliophyta – Flowering plants
Class	Magnoliopsida – Dicotyledons
Subclass	Rosidae
Order	Fabales
Family	Fabaceae – Pea family
Genus	Parkinsonia L. – paloverde

Because of its brilliant yellow blossoms in the spring, the palo verde is one of my favorite trees. Quoting from The United States National Arboretum:

The name “palo verde” means “green branch.” The trees have thin green bark on their trunks and branches. During dry times, which may be most of the year, the tree will shed its delicate leaves to conserve moisture. The plant can continue to photosynthesize through the chlorophyll in its trunk and branches. Arizona’s palo verde is a true desert dweller, and it frequently grows in the company of the saguaro cactus (Carnegia gigantea), which is Arizona’s state flower. The palo verde often serves as a “nurse plant” for saguaro cacti -- the cactus seedlings require a shaded, moist environment in their first few years of growth. The palo verde is an attractive small tree increasingly used as a street tree in the desert southwest. In spring the branches are covered with bright yellow flowers, and the green trunk adds interest through the rest of the year. Three similar palo verde species are native in the Sonoran Desert of Arizona. There is also a hybrid palo verde, Parkinsonia ‘Desert Museum’ possessing favorable characteristics for landscaping use. The legislation designating Arizona’s state tree does not select a particular species of palo verde, but only specifies the genus Cercidium. Studies of the North American Cercidium showed that our palo verde species belong in the same group as the African Parkinsonia. This group of plants has been reclassified as Parkinsonia, since this was the earlier name in use.