The palo verde tree, Parkinsonia spp., is well known to residents of the desert southwest and Mexico, yet there are few studies of it in the technical literature. As a drought-resistant, woody plant, it is unique in several ways, most notably its bright green trunk, stems, and petioles where most photosynthesis is performed. Stem photosynthesis is, however, not unique to this desert plant. Other unusual features of the palo verde plant include extensive root systems, heavily cutinized epidermis and vascular bundles, sunken stoma, very small leaves (leaflets), drought-deciduous behavior, idioblasts, C4 photosynthesis, and the plentiful accumulation of storage products, oil, starch, and calcium oxalate. These features make this plant uniquely fitted to thrive in arid, desert biomes. More work is required to clearly isolate and describe such tissues as the cambium, primary and secondary phloem and xylem bundles, and the extent of internal cutinization of this unusual woody plant. We conclude that the sum of these unique features make it purposefully fitted to the biomes in which it grows.