Plumier, parkinson, and the mexican palo verde,
parkinsonia aculeata

With the upcoming publication of Legumes of Arizona: An Illustrated Flora and Reference, we plan to take a closer look this year at several of the illustrations prepared for the book and explore some of the characteristics of plants in the legume family.

Shown here is a drawing of Parkinsonia aculeata, the Mexican palo verde, by Phoenix artist Susan Ashton. Sometimes called the Jerusalem thorn, the tree bears some very nasty thorns, as noted in its specific epithet, “aculeata”, or prickly. It is often called, affectionately or not, a self-mulching tree because of its prodigious leaf litter, which is actually an accumulation of the dried rachillas, or midribs, of the leaves. A tough and determined tree, Mexican palo verde is now distributed widely throughout the world in tropical, sub-tropical, and Mediterranean climates and is considered generally an invasive nuisance.

And yet it is a beautiful tree, with its long, drooping, graceful leaves and bright yellow orange-spotted flowers (a favorite of orioles). Note in the enlargement of Susan’s illustration of the palo verde flower that only the topmost petal is spotted. Once pollinated, that spotted petal, or banner, turns a reddish orange and folds forward. This movement can be seen in the side view of the flowers in the drawing where all the petals have been removed except for the banner.

Parkinsonia aculeata was first described by a Minim friar, Charles Plumier (1646–1704). Plumier, a botanist, skilled draftsman, and painter, made three journeys to the French Antilles, beginning in 1689. His first collecting expedition was so successful that he was appointed royal botanist to Louis XIV, who supported Plumier’s next two expeditions, in 1693 and 1695. On his third voyage he visited Guadeloupe, Santo Domingo, and Martinique where he encountered Parkinsonia aculeata. In 1703, he published Nova plantarum americanarum genera, with his description and drawing of Parkinsonia aculeata. Plumier died the following year of pleurisy, leaving an enormous body of work unpublished, including some 6,000 drawings.

A selection of illustrations from Plumier's first work, Description des plantes de l'Amérique (1693), written after his first expedition, as well as from his Nova plantarum americanarum genera, written ten years later after his third expedition, can be seen in this gallery.

Cactus lovers might be interested in the fact that Plumier, during his first journey to Martinique, determined cochineal—the Opuntia parasite and invaluable source of red dye for the European textile trade—to be an insect. While it’s hard to believe that this was even a question, at that time no one was quite sure what the substance of cochineal was, and it was generally considered to be a product of the cactus from which it was harvested, perhaps a seed. Plumier was widely derided for declaring cochineal an insect, but 13 years after his death, Claude-Joseph Geoffroy (1685–1752), a French chemist and apothecary, with the assistance of rehydration and a microscope, proved Plumier to be correct. In the third illustration shown on the right, cochineal insects, Dactylopius coccus, can be seen in the upper left of the painting (hover over the image to activate the zoom tool). The winged male insects are shown in Figures 8 and 9. Females, with no wings or easily observable legs, are shown in Figures 10 and 11. Without magnification, you can see why the cochineal scale was such a mystery.

Plumier named the genus Parkinsonia to honor John Parkinson (1567-1650), an apothecary and one of Britain’s first botanists. Parkinson served as official apothecary to King James I and was later named royal botanist by King Charles I. He was also an ardent gardener, and his book, Paradisi in Sole Paradisus Terrestris (1629), is considered to be the first book on gardening to be published in England. The elaborate frontispiece from the work can be seen on the right. It contained descriptions of some 1,000 plants with 800 illustrations, divided into three parts: the flower garden, the kitchen garden, and the orchard.

Woodcuts from the three sections of Parkinson's Paradisi in Sole Paradisus Terrestris can be seen in this gallery.

More of Susan Ashton's work has been included in past issues of The Desert Breeze. Marina parryi (Parry's false prairie-clover), another drawing prepared for the legume publication, and Fouquieria columnaris (boojum) are in the December 2013 issue along with a brief biography of the artist. Her drawing of Parkinsonia microphylla (foothill palo verde) can be seen in the January 2017 issue. More of Susan's work, including her drawings for the legumes project, are on her websiteCindy Hartwell

An abbreviated version of this article appeared in the April 2018 issue of the Desert Breeze, the monthly newsletter of the Tucson Cactus and Succulent Society.