Essays
Moseying: Exploring the Natural World
Endemic plants and drought adaptive horticulture
“An endemic species is a species that is found only in one region.” I have given this definition a thousand times along the trails at the Sibley Nature Center. Cory Ephedra is a species of plant found only in sandy soil from Monahans to Snyder – growing nowhere else in the world. Endemic species of plants and animals are adapted to very specific conditions, and over the years I have become obsessed with finding a number of the endemic plants of West Texas.
Many species have evaded me because their locations are on private property, far from a public road. These species often only have a few hundred extant individuals, as far as is known to science. These species of few numbers are often on the endangered species list, but not all are, since it takes years for such official designation to occur. The issue of endangered species is fraught with political intrigue as well, with powerful opposing lobbies keeping the process in a bureaucratic deep freeze.
Plants are a perfect example of the difficulty to devise taxonomic clarity. Years ago I collected a handful of the endangered puzzle sunflower from its limited range along the Pecos River and brought them home and planted them. I had 30 plants germinate and they grew well, finally producing seeds. However, I did not carefully pollinate the plants myself and the bees merrily mixed the puzzle sunflower pollen with that of our native sand sunflower. The next year I had more sunflowers, but no longer of a pure species. The plants had characteristics of both species. Because of the ease of hybridization, some theorists say they are not separate species at all, but merely site-specific forms. This adds to the debate about endangered species.
Deborah’s focused interest in medicinal herbs led us to another endemic species. Goatbush allthorn is not as limited in range as the puzzle sunflower. In the United States it can be found from Langtry to the mouth of the Devil’s River, and in similar rocky limestone hills in northern Mexico. It is not plentiful in its appropriate habitat – one does not see a field of goatbush allthorn. It is a small spiny shrub with small leaves. Its bark is very bitter – which led to its use in controlling amoebic dysentery. In many cases an extract of the bark in a tea will kill the disease-causing organism.
As someone interested in potential ornamental species of drought adapted plants, I spend time carefully going through regional plant identification books looking for specie that may do well. Some catch my eye and then I go to seek them out. Two species of boouchea continue to evade me. These small shrubs have pretty blue flowers.
One species only grows in the roughest part of the Dead Horse Mountains of Big Bend National Park. Despite that it grows along a specific stretch of road, I have failed to identify it (partly because I have never been there in its blooming season.) Its small round leaves tightly pressed to its stem are too similar to other species for me to recognize it while it has no flowers.
The other species grows along the Fort Stockton to Sanderson highway on a ridge between two canyons (as well as on private land), but try as I may by stopping and walking along the roadside, it too has avoided me for the same reasons. There are fewer than 50 people scouring the desert new ornamental plants for the garden and to my knowledge no one has successfully located or propagated the boucheas.
My specimen of goatbush allthorn came from such an individual. I have in its proper habitat only three times since learning of the species. Despite having grown it for several years and becoming familiar with its cultivated appearance, I have not spotted it in the wild.
Other species need such specific soils and water regimes that I can not grow them, despite finding specimens for sale or receiving them from other plant enthusiasts, or even propagating them myself. Mexican oregano is a popular plant in local gardens, especially among those belonging to those who garden to attract hummingbirds. Its pink and white tubular blossoms are present from July until frost. At the grocery store in the spice racks, folks can buy the dried leaves to use in place of regular oregano – it has a subtle difference.
Mexican oregano has two close cousins with very limited ranges. One is found on rocky slopes to the north and east of Big Bend National Park, and is not accessible without permission from landowners who are very active in private property rights issues. Possibly someday the chance for economic development of the species will lead the landowners to consider propagating the plant themselves for sale, but it is unlikely, because once the first plants are sold, other people will be able to propagate it.
I have visited the site of the other cousin to Mexican oregano. It is known as rosemarymint. It grows in sand dunes of gypsum just west of the Guadalupe Mountains. I found one specimen in a yard in Dell city, but nobody answered the door when I stopped to ask how they propagated it. The day before, I had been given a tour of the northern end of the gypsum dunes where it grows on what was then Nature Conservancy land. Dean Ricer, former director of the Living Desert State Park in Carlsbad, N.M., an avid and superb plantsman who amazingly recreated a gypsum arroyo atop a limestone hillside at the park by moving in 60 dumptrucks of the proper soil and then planted many of the endemic gypsophilic plants. He reported he had successfully propagated rosemarymint by cuttings, but that it kept dying for unknown reasons when planted outside. He later gave me one of his rooted cuttings, but I lost it as well.
Pursuing endemic plants gives another focus to daytripping. I revisit some of the species I have found over the yars, and those that I have failed to propagate I will try again. At the Madera Canyon roadside park in the Davis Mountains, silver dichondra is scattered about. Over the last 30 years I have taken cuttings at least three times and have failed each time, but someday – someday -- I will succeed!