Yuccas

Yucca flaccida, Yucca
Yucca flaccida, Yucca

Often when I’m out on a group hike, we come across plants that some are surprised to see in Arkansas. One of those plants is yucca. In fact, that are five species of Yucca recorded from Arkansas, including two or three from Carroll County, depending upon botanical whim. Botanists are so adept at changing plant names, that if they were put in charge of naming planets, we would surely wake-up one morning to discover that we no longer live on a planet called Earth. Telling Arkansas’s five yucca species apart from one another takes a good deal of chin rubbing.

Yucca elata
Yucca elata

Fortunately for lay-folk consumers of botanical knowledge, the common name yucca is the same as the genus name—Yucca. One species of Yucca here in Carroll County has a name that’s easy to remember —Yucca arkansana which is kin to Yucca louisianensis due to inbreeding or some other evolutionary exchange of genes in the pre-human past. In 2014, the late Dr. George P. Johnson, a botanist at Arkansas Tech in Russellville found Yucca freemanii in Miller County. Besides these three native species, Yucca filamentosa and Yucca flaccida occur here but are not native to Arkansas; they are naturalized. In other words, they were planted at some point and now grow and reproduce without the help of humans.

Yucca schidigera, Mojave Yucca
Mojave Yucca

In North America (north of Mexico) there are twenty-eight species of Yucca. Yuccas have been used for thousands of years for food, beverages, detergents, medicines, construction material, and especially as a fiber plant. During the First World War, 80 million pounds of yucca fiber were used to make course bags. The U.S. Navy used a special heavy paper made from yucca fiber during material shortages of the Second World War. Over the centuries, among indigenous groups of the American Southwest, yuccas were the foremost wild plants used for material necessities.

One National Park in California is named after a yucca (Yucca brevifolia) the 792,683-acre, Joshua Tree National Park. President Franklin Delano Roosevelt decreed it a National Monument in 1933. In that same year, a cousin of Roosevelt’s, Susan Delano McKelvey, published a paper on yuccas in the Journal of the Arnold Arboretum of Harvard University where she worked as a research associate and valued patron. So which came first, the President’s decree or his cousin’s interest in Joshua tree and other yuccas? Later, she wrote the definitive two volume work Yuccas of the Southwestern United States. My vote goes to Roosevelt’s cousin.

Yucca brevifolia; Joshua Tree
Yucca brevifolia, Joshua Tree

Swooned by the Sweet Black Locust

By Steven Foster |

Black Locust, Robinia pseudoacaciaSeveral times in the last week, people have asked what is that tree with the white or pinkish pendulous clusters of pea-like flowers? It is Black Locust (Robinia pseudoacacia), a very  early introduction from North America to Europe. Go almost anywhere in Europe or temperate Asia today, and the “Virginia acacia”—our Black Locust—is widely planted as a street tree, and appears as if part of the native landscape. In his 1823 Sylva Florifera, Henry Phillips, tell us that American Indians made a declaration of love by presenting a branch of this tree in blossom to the object of their attachment. No doubt our native Black Locust itself was the object of desire. “Of all exotic trees,” Phillips writes, ” with which we have adorned our native groves, this North American stands first”.

Black Locust, Robinia pseudoacacia
Black Locust, Robinia pseudoacacia

Our common Black Locust was fancied by early missionaries to be the Egyptian acacia that supported St. John in the wilderness. They were wrong, so it was called “false acacia,” thus the species designation “pseudoacacia.” It was introduced to Europe at a very early date and planted with religious zeal.

The name Robinia honors Jean Robin (1550-1620) a ParisianBlack Locust, Robinia pseudoacacia apothecary recognized as one of the best French botanists of his time. Henry III appointed him herbalist and arborist at the gardens of the Louvre. His son, Vaspasian Robin (1579-1660) continued his father’s work and planted the tree in the Jardin des Plantes in Paris by 1636. John Parkinson (1567-1650) first described it in his monumental Theatrum Botanicum (Theatre of Plants), published in 1640. By the 1660s our woodland waif was widely planted as a street tree throughout Paris and London.

Black Locust, Robinia pseudoacaciaThe love affair continues over 400 years later. Just last week, I posted a photo of the flowers on Facebook, and a friend from Turkey noted it is common avenue tree there, and that as a child, he ate the flowers. Other chimed in that the sweetly fragrant flowers dipped in cool water are delicious, or that dressed with oil and balsamic vinegar, the flowers are a nice addition to salads, and are great added to pancakes. The heady fragrance was blamed, too, for inducing nausea and headaches, though that accusation has the odor of a swooning Victorian suffering from unrequited love. For better or worse, this is one American tree that we rediscover each spring!


A bee-friended Black Locust, Robinia pseudoacacia
A bee-friended Black Locust, Robinia pseudoacacia

Ginkgo Leaves Falling

By Steven Foster.

The brilliant golden yellow leaves of the Ginkgo trees flanking the back entrance of our local post office, once they are ready to fall, will  drop in a few hours time, raining from the thick branches like small fans twirling from the sky. After our first hard killing freeze last night, the Ginkgo leaves fell today.

Ginkgo tree with golden leaves on 11 November 2013
Ginkgo tree with golden leaves on 11 November 2013
The same Ginkgo tree on 13 November 2013, minus its leaves.
The same Ginkgo tree on 13 November 2013, minus its leaves.

The shriveling fruits, which look like half-sized wild persimmons, may persist for a few days after the leaves, then fall to the ground. Fruits are always a tempting curiosity. In fact, you can buy Ginkgo seeds as a food item in Chinese markets, but these have been prepared and processed to render them safe to eat. You should not be tempted to pick-up the freshly fallen fruits, which will cause contact dermatitis similar to the rash produced by poison ivy. The fruits have a fragrance that has been described as a blend between baby vomit and what a dog might leave on a sidewalk. That should be enough to entice you to leave them be.

I suspect that these trees were planted about the time the Eureka Springs Post Office building was completed in 1918, rather than in 1973 when the building was expanded and the service parking lot in the back was developed. The trees are of a fairly good size, plus for many decades most ginkgo trees available from nurseries in the United States have represented male branches grafted on to rootstocks. Within forty years after Ginkgos were widely planted as a street tree by the mid 1800s, female trees like those at Eureka Spring’s Post Office began to leave their bad smelling fruits on sidewalks. Female Ginkgos are simply not a neat and tidy street tree. Notwithstanding the beauty of the fall foliage, the fact that these two trees are females makes them a unique and interesting part of Eureka  Springs’ heritage.

Beneath the Ginkgo tree, 13 November 2013
Beneath the Ginkgo tree, 13 November 2013

Ginkgo was common 175 to 200 million years ago, when dinosaurs roamed the earth.  This primitive tree is considered the oldest living tree species on earth.  Ginkgo is monotypic. That is, in the ginkgo family there is only one species in one genus — the only surviving member of the ancient and primitive ginkgo family—Ginkgoaceae. Ginkgo has been cultivated in East Asia for hundreds of years. Numerous reports mention the existence of large specimens, some more than a thousand years old, at ancient temples in Japan and China. The tree was first introduced to North America in 1784 in the garden of William Hamilton at Woodlands near Philadelphia.  Mature ginkgos are said to reach over 100 feet in height.  Its longevity as individual trees and a species in general can in part be attributed to its exceptional resistance to pests and resiliency to destruction by fire. It is also extremely tolerant of air pollution thriving in the harshest urban environments.

Ginkgo leaf extracts are highly complex, highly concentrated preparations with an average  ratio of 50 parts ginkgo leaf to one part of the finished extract by weight. Numerous chemical constituents are found in the extract. Normally ginkgo leaf extracts are calibrated to contain 24 percent flavone glycosides (but may range from 22 to 25 percent) which are a relatively ubiquitous group of compounds found in numerous plant species.  Another important compound group in ginkgo leaf extracts are mostly unique to ginkgo — the ginkgolides — including ginkgolides A, B, and C (around 3 percent) and bilobalide (also about 3 percent). As the oldest living tree species on earth, it is no surprise that it would harbor chemical components rare in nature. Perhaps these extremely complex, large molecules have helped it survive for eons. In addition, during the manufacturing process another group of compounds, ginkgolic acids, which are perceived as potentially toxic, are reduced to below 5 parts per million. Given the specific chemical make-up of ginkgo leaf extracts, it  becomes clear why you can’t apply the results of studies with Ginkgo leaf extracts to a simple tea made from ginkgo leaves. Ginkgo tree, Ginkgo leaf, Golden autumn Ginkgo leavesNumerous pharmacological and clinical studies on Ginkgo leaf extracts have demonstrated a positive effect in increasing vasodilation and peripheral blood flow rate in capillary vessels and end-arteries in various circulatory disorders, varicose conditions, post-thrombotic syndrome, chronic cerebral vascular insufficiency, short-term memory improvement, cognitive disorders secondary to depression, dementia, tinnitus, vertigo, antioxidant activity, among other effects.

Ginkgo tree, Ginkgo leaf, Golden autumn Ginkgo leaves