Taxonomy (also called Systematics) is a branch of Biology dedicated to describing, classifying and naming organisms.  It is a science that tries to reconstruct the phylogeny or evolutionary history of living and long dead (fossil remains) organisms in hopes of understanding their origins and relatedness.  Taxonomists assign organisms a scientific name or Latin binomial (two names) identifying them as a genus and species.  These names, like Zea mays in the case of corn, are useful within the scientific community as they allow scientist an agreed upon name when discussing specific organisms.

For all the apparent intellectual rigor, scientific names, particular within Botany, have been remarkable fluid and over the last half-century have change repeatedly.  For example, within the desert landscape palette the genus Senna was changed to Cassia and then recently changed back to Senna.  Our Arizona Native Mesquite, Prosopis velutina, was once considered a variety of P. juliflora (as P. juliflora var. velutina), but is now considered an unique species.

While it has been traditional for general biologist, especially biology students, to make fun of taxonomist for their inability to make up their minds, their work is difficult, complex and academically important.  Imagine you are at the top of a Ferris Wheel on the opening day of the county fair.  From this vantage point you look down on the crowded midway below and try to determine which of the people below are members of the same family. From this height you could only use criteria visible from such a distance like color of clothing, perhaps hair color, how they were aggregated, behavior or possible physically connected (holding hands, hugging, standing in groups).  As the wheel nears the ground and more details can be discerned, you might be inclined to create entirely different groupings using different criteria.  As technologies and methodologies improve the biologist’s view of the living world the taxonomist must reevaluate previously agreed upon groupings of organisms on the basis of new and improved data.  Ultimately changes in taxonomy must be carefully considered with the goal of creating greater understanding of the living world.

Botanists use taxonomy as a means of discussing and studying plants in an academic context.  Professional horticulturists use both common and scientific names (Latin binomials) almost interchangeably which in itself can lead to misunderstandings. Among state and local plant regulators these names represent units of commerce or regulated items (e.g. ADWR Approved Plant Lists). Changing the botanical names of commercially important landscape plants can create confusion among growers, landscape architects, contractors, regulatory officials and the end users.  With these factors in mind, botanical name changes, especially among commercially important species, should be carefully considered, well researched and ideally, as with all scientific work, published in respected and reviewed publications.

Arid Zone Trees has elected to adopt the taxonomic scheme published in 2001, by Felger, Johnson and Wilson in their book The Trees of Sonora, Mexico (Oxford University Press, New York, New York).  This book represents the most recent comprehensive taxonomic review of plants native to the Sonoran desert.  As a courtesy to our clients and to aid in the transition to these new names AZT will continue to reference the previous botanical name along with the revised ones on all documents.  These name changes are as follows:

New Name                                              Prior Name                                           Common Name

Acacia farnesiana                                 A. smallii, A. minuta                             Sweet Acacia

Parkinsonia florida                               Cercidium floridum                               Blue Palo Verde

Parkinsonia microphyllum                  Cercidium microphyllum                     Foothill Palo Verde

Parkinsonia praecox                            Cercidium praecox                               Sonoran Palo Verde

Parkinsonia x “Desert Museum"        Cercidium x “Desert Museum”           Desert Museum Palo Verde

Parkinsonia x “AZT”                             Cercidium x “AZT”                                AZT Hybrid Palo Verde

Ebenopsis ebano                                 Pithecellobium flexicaule                    Texas Ebony

Havardia mexicana                              Pithecellobium mexicana                   Mexican Ebony

Havardia pallens                                  Pithecellobium pallens                        Tenaza

Prosopis velutina                                 Prosopis juliflora                                   Arizona Native Mesquite