Ferns of the Monterrey Region, Mexico

Abstract

Monterrey is the largest city in northern Mexico and capital of the state of Nuevo Le6n. It is joined by the Pan American Highway with Laredo, Texas, and Mexico City. A good highway extends from Monterrey westward to Saltillo which is located on the one hundred and first meridian. Because of Monterrey's strategic position, it is visited each year by many people from the United States. Some spend a few days there and then return to Texas. Others simply stop overnight on the way to more distant points. Since accommodations for visitors are many and good, members of the Fern Society may wish to make this city their headquarters while they survey the interesting ferns of the mountains roundabout. All species which are listed below from the quadrangle (25?-26? N., 100?-101? W.) can be seen on trips of a day's duration from Monterrey. The area under discussion is semiarid, mountainous country. It is located towards the northern end of the eastern Sierra Madre, but on the west includes a portion of the central plateau and in the northeast a lobe of the Coastal Plain. The rocks are preponderantly limestone, with the strata much folded. Those of the mountains are of Lower Cretaceous or Jurassic Age, but those in the north and also the plateau and Coastal Plain portions are of Upper Cretaceous age. The altitudinal range is from 300 meters on the Coastal Plain to 3600 meters in the mountains. The temperature varies with the altitude, whereas the rainfall decreases westward and is least on the plateau. The following statistics from a paper on the climatology of Mexico by Contreras Arias (1942) indicate the situation: Villa de Santiago, long. 100? 8' W., alt. 445 m., aver. ann. temp. 21.7? C., aver. ann. rainfall 1039 mm. 89