Land of 

 the Mesquite 



The East Chaparrals of the North and South 

 Scrub Belts, and the Deserts of the Rio Grande 



About the mouth and lower reaches of the Rio Grande, on both 

 the Mexican and American sides of the border, lies a beautiful 

 land of somewhat varied appearance that is a veritable paradise 

 for the naturalist. This forms a triangle, fronting on the Gulf 

 coast and running inland to an apex about Eagle Pass. This 

 province lies between the great Prairie Belt on the north and the 

 subtropical savannahs on the south and thus is composed of 

 both the Northern and the Southern Scrub Belts and the Hot 

 Desert. However, due to the proximity of the warm waters of the 

 Gulf and the mild moist winds that move up the coast with the 

 circulation of those waters, it is clothed in a much more luxu- 

 riant growth of plants than it would otherwise be (and it does not 

 look anything like those scrub belts farther inland), whereas the 

 desert is here compressed to a mere line of somewhat greater 

 aridity. 



If we enter this province by land from the northeast across 

 the black prairies and oak belt, we come upon it suddenly at the 

 San Antonio River. Here the grass cover of the whole land 

 breaks up into patches and becomes scarce or nonexistent. The 

 massed oaks and Spanish Moss disappear, and in their place 

 stand delicately green, feathery-foliaged trees with dark trunks 

 and a general appearance of great cleanliness. We have entered 

 an entirely new country. 



The name of this tree, known as the Mesquit or Mesquite, is 

 derived from the Spanish mezquite, which in turn was a trans- 

 literation of the Amerindian Nahuatl mezquitl. It is a North 

 American plant belonging to the mimosa group of the pea or 

 leguminose family, which contains beside peas, beans, clovers, 

 vetches, alfalfa, lupines, and peanuts, many herbaceous flowering 

 plants, shrubs, and trees, and among the last the acacias. The 

 Mesquite (Prosopis juliflora) has feathery leaves, twigs armed 

 with sharp spines, and white spike-shaped inflorescences that 

 turn yellow. It bears pods about five inches long, containing 

 beans with a high sugar content. It also has a very fine, dense 

 wood much used in cabinet work today but in bygone times as 

 fuel; its beans are quite nutritious and are eaten regularly by 

 men and many animals, and its flowers are a good source of 

 nectar and pollen for bees. There are forty species of mesquites, 

 ranging all over the North and South Scrub and the desert belts. 

 Their mightiness stems from one of their particular aptitudes 

 and from a special feature of their physiology. 



Mesquites are essentially dry-area plants and can grow in 

 advanced desert conditions, but they are apparently originally 

 indigenous to the outer scrublands. They are extremely hardy 

 and rather fast-growing at first, and they can rapidly crowd out 

 other trees by grabbing the available soil moisture and dis- 

 pensing a fairly deep shade, all of which fosters their spread 

 throughout the chaparrals and the scrublands generally. How- 

 ever, it also has made it possible for them to spread in other 

 directions; and within the past three centuries they have done 

 so to such an extent in one direction, namely, onto the prairies, 

 that not only forestry men but stock-raisers and agriculturists 

 are becoming seriously alarmed. 



Mesquite, it is believed, was once confined to the scrub and 

 desert belts and is apparently indigenous to this province, com- 

 monly called the East Chaparral area. Today, it has spread not 

 only up and over the Balcones Escarpment (see map) but across 

 the Edwards Plateau on the east side to link up with the park- 

 lands and thence north to Kansas; and it is still going. To the 

 west, Mesquite has long since topped and crossed the Stockton 

 Plateau and spread up the Pecos valley; but there its presence is 

 not so alarming since so far it is confined to the strip of scrub- 

 land that goes that way. In the east it is considered a menace 

 because it is rapidly encroaching on the prairies, and once it 

 does so en masse it destroys the grazing and is difficult and 

 costly to eradicate. Some seventy-one million acres are already 

 so affected in Texas and Oklahoma alone. It seems that Mesquite 

 was originally kept off the grasslands by the indigenous fauna, 

 but since the latter has been virtually eliminated — especially the 

 bison herds and the prairie dogs — substituted cattle have been no 

 match for it. Also it acts as a firebreak, and natural grass fires 

 seem to have been one of the essential features in the mainte- 

 nance of the prairies as grazing lands for animals. 



The Mesquite is the dominant plant of the East Chaparral 

 Province, especially north of the Rio Grande, but two other 

 small bushlike trees run it a close second. These are the Huisache 

 (pronounced we-sa-chay) or Sweet Acacia (Acacia jarnesiana), 

 and the Huajilla (pronounced wa-he-ya) or Cat's Claw (Acacia 

 greggii), which is also often simply called the Chaparral. The 

 Huisache has beautiful, marble-sized, pufTball-shaped yellow 

 flowers, and its leaves are highly sensitive to touch. Some 

 huisaches are profoundly spinous, others lack spines, but the 

 cat's claws are like barbed-wire entanglements — hence their 

 name. These are the principal trees of the North Scrub Belt in 

 this province, at least on the coastal and inland plains north of 

 the Rio Grande; but they are associated with a large number of 

 other shrubs and herbs, all of which bear lovely flowers. 



THE HIDDEN DESERT 



Ignoring for the moment the coast on the one hand and the 

 upper or western part of the triangle on the other, let us imagine 

 ourselves traveling due south, first crossing the Rio Grande 

 valley and then continuing across the plain, on Mexican soil, to 

 the Ancient Mountains with the mighty Sierras standing behind 

 them. The land is first low rolling country, almost a level plain 

 cut by numerous west-to-east watercourses, each in its own small 

 valley. These are filled with profuse plant growth and quite 

 large trees. Many of these are quite deep and are called locally 



Prickly-pear cactuses form a large group now found wild 

 all over the United States and in many foreign countries, in 

 some of which they have become a serious blight. 



186 



