NATURAL AREAS AND REGIONS 



593 



Pithecollohium brevifolium, tenaza. 

 H offmanseggia melanosticta. 

 Cercidium jloridum, retama. 

 Eysenhurdlia polysluchya, tardy. 

 Parosela berlandieri. 

 Covillea gluiinosa, creosote bush, 



Gobernadora. 

 Koeberlinia spinosa, corona de cristo. 

 Fouquieria splendens, ocotillo. 



Mammals 



Pipislrellus hesperus hesperus, little 



western bat. 

 Canis microdon, small-toothed coyote. 

 Bassariscus astutus Jlavus, tawny 



bassariscus. 

 Felis pardalis griffUhii, ocelot tigrillo. 

 Lynx ruffus texensis, Texan Ijaix. 

 Baiomys taylori taylori, Taylor's little 



brown mouse. 

 Peromyscus leiicopus texanus, Texas 



white-footed mouse. 

 Oryzomys couesi aquaticus, Rio Grande 



rice rat. 

 Sigmodon hispidus berlandieri, Ber- 



landier's cotton rat. 

 Neotoma micropus micropus, Baird's 



wood rat. 

 Geomys personatus Iropicalis, Tamauli- 



pas pocket gopher. 

 Liomys irroratus texensis, Texas spiny 



pocket mouse. 

 PerognatJms merriami, Merriam's pocket 



mouse. 

 Dipodomys merriami merriami, Mer- 

 riam's kangaroo rat. 

 Citellus mexicanus parvidens, Rio Grande 



ground squirrel. 

 Lepus calij'ornicus merriami, Merriam's 



jack rabbit. 

 Pecari angulatus angulatus, Texas 



peccary. 

 Odocoileus hemionus canus, gray mule 



deer. 



Birds 



Callipepla squamata castanogastris, 

 chestnut-bellied scaled partridge. 



Amazona viridigenalis, red-crowned 

 parrot. 



Otus asio mccallii, Texas screech owl. 



Dryobutes scalaris symplectus, Texas 

 woodpecker. 



Platypsaris aglaiae aglaiae, rose- 

 throated becard. 



Otocoris alpesiris diaphora, Tamaulipas 

 horned lark. 



Heleodytes brunneicapillus couesi, Coues' 

 cactus wren. 



Thryothorus ludovicianus berlandieri, 

 Berlandier's wren. 



Toxostoma longirostris sennetti, Sennett's 

 thrasher. 



Xanlhoura luxuosa glaucescens, Rio 

 Grande green jay. 



Icterus melanocephalus audubonii, 

 Audubon's oriole. 



Icterus cucullatus sennetti, Sennett's 

 oriole. 



Arremonops rufivirgatus rujlvirgatus, 

 Texas sparrow. 



Pyrrhuloxia sinuata texana, Texan 

 pyrrhuloxia. 



Richmondena cardinalis canicauda, gray- 

 tailed cardinal. 



D. MODIFICATION OF ORIGINAL BIOTA 



While much of Mexico remains in 

 essentially primeval condition important 

 changes have been brought about 

 through human occupation, especially 

 near the larger cities. On the higher 

 parts of the Plateau near its southern 

 end many of the more fertile sections of 

 original grassland, or mixed grassland 

 and scrub have been turned into fields 

 of wheat, corn, beans, century plants or 

 magueyes for the production of pulque 

 (a fermented drink), mezcal and tequila 

 (distilled liquors), fiber, and other crops. 

 The grazing of such domestic stock as 

 cattle, horses, burros, sheep, and goats 

 is extensively carried on wherever 

 conditions are suitable throughout the 

 Republic; and this, as elsewhere, has 

 resulted in the overutilization of forage 

 in places, especially in the vicinity of 

 water. Large sections of the northern 

 tier of states remain but little modified 

 owing to extreme sterility and scanty 

 forage production, or to the absence of 

 a permanent water supply for stock. 



Within the tropical zone much of the 

 original forest is still intact. Cultiva- 

 tion of the soil here usually involves 

 the clearing of forest for growing a 

 variety of crops including corn, beans, 

 sugarcane, cotton, coffee, cacao, and 

 many kinds of fruit. Coffee is grown on 

 humid tropical mountain slopes to 6000 

 ft. altitude. A considerable section 

 of northern Yucatan is devoted to the 

 cultivation of a native century plant 

 {Agave ixtli) from which is extracted 

 the "ixtle" or "henequen" of commerce. 

 The production of this fiber, extensively 

 used as binding twine, constitutes one 

 of the more important Mexican in- 

 dustries. As a result much of the 



