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 to 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 a unique species.
It is easy to trivialize the work of taxonomists 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, taxonomists 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 biosphere.
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 both retail and wholesale 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 science publications. Within the commercial sphere, there needs to be some flexibility with the interpretation of “new” plant botanical names so they don’t compromise approved landscape plans and existing plant inventories.
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 mexicanum Pithecellobium mexicanum Mexican Ebony
Havardia pallens Pithecellobium pallens Tenaza