The traveler who has viewed the Southwestern panorama of nature from its sagebrush to its spruce trees has indeed seen most of it. The spruce which grows wild only well up on the higher mountains is familiar to everybody because it has become a favorite in formal planting everywhere. But the sages—who knows them? To the tenderfoot, almost any gray plant is “sage.” To my friends the cowmen, sage means commonly saltbush. To my friends the foresters, sage means an artemisia. But there are romantics to whom “purple sage” is Apache plume, which is a member of the wild rose family.
Some popular education would seem to be desirable. And this applies, too, to the cacti, for there is more misinformation about them than anything else that grows, runs, or creeps—except rattlesnakes. The clever people who design travel folders and pictorial maps almost always put saguaros in New Mexico. But saguaros do not grow in New Mexico. That is final! And the yucca is not a cactus. That also is final. Nor yet the ocotillo—that defiant, splendid denizen of the desert which flaunts the scarlet torch of flowers. The question that is always on the surface as one writes of plant life in the Southwest is, “Who wants to know?” The picnicker wants to know the names—and nothing much besides—of the wild flowers. My friend the cowman already has the names; that is, the common ones. If I chance to mention blue grama grass, he gently corrects me, “black grama.” Then if I mention black grama, he says, “no, white grama.” But at least he is concerned about something more important than nonscientific names. He wants to know if the plant is something that a lean old cow can eat, whether it stays green in winter, and if it will hold the soil in place. The tourist who pilots car and passengers some six hundred miles between breakfast and bedtime asks only what he was looking at. The rest of us who go into the mountains often enough to be impressed by the layer-cake succession of plants on their slopes can, with the aid of some reading, amass a store of knowledge where others amass only mileage. On a tour, it is mileage or knowledge. One has to choose.
Actually, our New Mexico desert is not dominated by sage. That honor is held by the creosote bush, called by some of the old-timers greasewood, Covillea glutinosa, by some of the scientists—along with five other synonyms. Like the mesquite with which it shares the same general habitat but does not intermix, it occupies an immense spread of territory, roughly from Texas to California. Since no livestock will eat it and the ground it occupies is equally useless for agriculture because of aridity and stoniness, creosote is a veritable coyote for survival. The traveler descending from Taos to Santa Fe need not look for it. The sage of that locality, which gives the landscape its singularly mournful aspect, is a true sage. With good reason the cowboys call it black sage.
In 1846, Lieutenant Emory, as he rode southward with the Army of the West, first encountered the creosote as he approached Socorro. The northward extension of the plant is at the same point today, and the range of mesquite extends only a few miles farther north. These two remarkable plants are the main markers of the Lower Sonoran Zone. In the same arid, stony, broken country, the traveler will find an abundance of cacti, and these plants are usually supposed to be the most tenacious of all tenacious growing things. Actually, in southwestern Arizona and neighboring parts of California there are whole areas where the aridity is too severe for cacti, but for our state—let it stand. Everybody, of course, has noted the grotesque shape of the plants, but not everybody has noted that the shape was chosen with a canny intelligence. A globe exposes less surface (that is, the vulnerable area for evaporation) than any other solid of equal volume. And a cylinder is second best. Another thing—cacti being succulents are filled with a watery sap or juice which quickly coagulates after a wound and stops the waste of moisture. Furthermore, the plant’s aggressive root system is arranged so as to capture the grounds scanty moisture most quickly and completely after rains.
Cacti of more than sixty species occur within our state, but more than nine tenths of the plants seen along the highway—unless they are brought together for a garden collection—can be grouped into one genus, the Opuntia. The family likeness is shown not by the shape or general appearance but by the fact that all are jointed. Both the cane cactus (also called cholla and elkhorn) and the pancaked prickly pear, unlike the big barrel cactus and the numerous small species which resemble it in shape, have joints and may therefore be rightly called opuntias. The “pancakes,” it may be remarked, are not leaves but divisions of the stem. A cactus gets along without leaves. So a good rough-and-ready test is this: if it has leaves, it is not a cactus—which eliminates ocotillo, yucca, agave, sotol, and so on.
The barrel cactus is sure to be seen growing beside service stations in the southern part of the state. Its name as well as its size identifies it. The flowers and the large lemon-shaped fruits are worth a glance. If they do not occur on the south side of the plant, it has been transplanted and turned. The evidence is as trustworthy as the presence of moss on the north side of a tree in the forest.
The barrel cacti, the opuntias, acacias, the ocotillos, along with the creosote and mesquite already mentioned, have a way of growing along together in what is called a plant society. These all belong in the bottom layer of the cake called the Lower Sonoran Zone, which is best seen on the Rio Grande mesas near El Paso.
The layer next above it comprises the foothill country of the Upper Sonoran Zone, which includes most of the state of New Mexico. Some of its common markers are juniper, piñon, oak of various species including live oak, mountain mahogany, mescal, yucca, beargrass, and the famous blue grama grass. It is exhibited all along the Continental Divide in the southwest part of the state but nowhere so well as in the Fort Bayard Reservation. There a tract, protected for three generations from woodcutting, fires, and intensive grazing, offers a large-scale picture of the lovely land that once was New Mexico. There the character and amount of vegetation astounds the visitor who is familiar with only the close-picked, parched aspect of the landscape that generally borders the main highways. When seen from the air, the very color of the grass-mantled earth is many shades lighter than that of the bare overgrazed ranges a few miles to the south. And the difference can be seen by anybody.
The foothills are dotted, not covered, with juniper and piñon. The dwarfed, rounded little junipers (properly enough called cedars) leave the traveler unprepared to believe that they will anywhere become respectable forest trees. Yet in the Burro Mountains, the alligator-bark species, finest of them all, reaches a diameter of five feet and an age of about 1000 years. The wood has an extraordinary fragrance, and its smoke tells the neighbors for blocks around that you are warming yourself at the fireplace. Another notable thing about the wood is its resistance to decay in the earth. I have removed pieces of it from subterranean ruins of the Mimbres culture which, according to the best archaeological opinion, are some eight hundred years old.
The yuccas deserve a story by themselves. One small, unimpressive species greets you on the meadows at the foot of Raton Pass; others have to be searched out along high limestone ridges where the foothills are deciding to become mountains. The one chosen for our state flower is the tall yucca (Yucca elata), a superb species best seen along the Continental Divide near Silver City. The genus reaches its greatest size in the grotesque Joshua tree, which never fails to attract the eye on the Mohave desert in California.