TABLE OF CONTENTS. VII 



List of trees of the Mexican Boundary Lin< — Continued page. 



Holacantha emoryi (Holacantha) 62 



Kceberlinia spinosa | Kceberlinia; junco) »'»"> 



Freniontodendron californicum (Fremonl tree). 63 



Rhus integrifolia (Western sumach) 63 



Acer saccharum grandidentatum i Largetooth maple i 63 



Acer negundo ( Boxelder) 63 



[Jngnadia speciosa (Texas buckeye; Mexican buckeye) 63 



Sapindus marginatus (Wild China tree) 64 



Rhamnus crocea ( Evergreen buckthorn) 64 



Rhamnus purshiana (Bearberry) (i -t 



Zizyphus obtusifolius I * )btuseleaf zizyphus 1 64 



Cereus giganteus (.< riant cactus) 64 



Cereus thurberi (Thurber cactus) 66 



Cereus schottii (Schott cactus) ,i( > 



Opuntia fulgida (Choya) 66 



Opuntia versicolor (Tree cactus) 66 



Opuntia spinosior (Sigura) 66 



Arbutus arizoniea (Arizona madrona I 66 



A.rctostaphylos pungens i Manzanita) 67 



Bumelia rigida ( Shittimwood) 67 



Brayodendron texanum (Mexican persimmon) 67 



Fraxinus cuspidata ( Fringe ash ) 67 



Fraxinus velutina ( Leatherleaf ash ) 68 % 



Chilopsis linearis ( Desert willow ) 68 



Sambucus mexicana ( Mexican elder) 68 



Saml )ucus glauca ( Pale elder; sanco) 69 



Introduced species of trees, now growing without cultivation on the Mexican 



Border of the United States 69 



Chamaecyparis (Cedar) 69 



Ficus (Fig) ' 69 



Melia azedarach I ( Ihina tree; Pride of India) 69 



Schinus molle ( Pepper tree ) 69 



Eucalyptus. 69 



Nicotiana glauca ( Coneton ; Tronadora; Tobacco ) 70 



Life Areas of the Mexican Boundary Region ., 70 



Differentiation tracts 73 



Descriptions of principal collecting stations 71 



Summary of collecting stations L43 



Mammals of the Mexican Boundary Region L49 



Order Marsupialia 150 



Family J Udelphiidse 150 



(Jen us Didelphis 150 



Key to the Species of I >idel ] >1 lis foil ml on tlie Boundary Line. 150 



Didelphis mesamericana texensis 150 



virginiana 153 



l >rder Edentata L56 



Family Dasypodidse 156 



Genus Tatu 157 



novemcinctum '•" 



Order Ungulata 158 



ban lily Tayassuidse 159 



( ienus Tayassu ' • >1) 



a nun latum 160 



sonoriense 162 



