The Chilean Mesquite (Prosopis alba) tree is popular in Southern Arizona because of its rapid growth, lower water requirement and ability to provide shade. Native to South America, the Chilean mesquite grows either singly or multi-trunked reaching a mature size of 30' tall with a 40' or greater spread. Its trunk appears twisted with dark, coarse textured bark. One of the usually small paired appendages at the base of a leafstalk in certain plants, similar to roses and beans.

The Mesquite is considered one of the ten oldest species known on the planet. It is told that this plant is the only plant in Arizona that will never bloom before the last freeze of the year, where other palnts will be fooled by Indian summer and bloom early.

The thorns can grow up to 3" long are unevenly present. Chilean mesquite tree is semi-dormant, from December to April, shedding most of its foliage in the winter. Small, catkin-like flowers appear in the spring. The flowers are followed by light brown elongated seedpods that ripen and fall to the ground in the summer to create leaves a light brownish-yellow carpet.
The ChileanProsopis alba is a South American that inhabits the center part of Argentina, the Gran Chaco ecoregion and part of the Argentine Mesopotamia. It is known as Algarrobo Blanco. In Spanish, which means "white carob tree" (the Spanish settlers gave it that name because of its similarity to the European carob tree). Other common names come from Guarani: Ibopé and Igopé.

Prosopis alba is a medium-sized tree, that grows to a maximum 49 ft. high and about 3ft in diameter, though such tall specimens occur very rarely at present. The trunk is short and the canopy is globular—sometimes reaching 33 ft in diameter. The bark is thin, brown-grayish in color, with streaks, and it has bark that changes as it tans depending on exposure to the sun.
The tree has ornamental and utility uses, both as windbreaks and timber, which is rather dense and ideal for vintage- and rustic-style furniture, doors and floors, for paving blocks, shoe lasts and wine. The wood responds well to drying and is therefore valuable for work that requires stable dimensions regardless of humidity. It is also durable for outdoor use.

The main parts of a shoe lasts.
The flowers are small, greenish-white or yellowish, and the  pollination is called bisexual polination, mediated by wind and insects, is cross pollinated, since the female reproductive organs are turned active before the male ones.

The fruit is a seed pod which grows up to 8 inches long, with brown seeds about 1/4 inch long. The plant produces a sweet floury paste (like patay), which very high in energy, that can be used for fodder or turned into flour or human consumption. In the 1940s a mildly intoxicating beverage called aloja was made from it through fermentation; in turn it was sometimes distilled to produce ethanol. Between half and three quarters of the fruit's weight is sugar.

The tree can reportedly tolerate drought, salt and sand; in fact, it is extremely efficient with regards to water consumption, it produces the most fruits in years of drought and has been successfully introduced in arid terrains. However, it cannot stand even mild frost. Edited from Wikipedia.com