TABLE OF CONTENTS. VII 



List of trees of the Mexican Boundary Line — Continued. Page. 



Holacantha emoryi (Holacantha) 62 



Kceberlinia siainosa (Koeberlinia; junco) 63 



Fremontodendron calif ornicum ( Fremont tree ) 63 



Ehus integrifolia ( Western sumach ) 63 



Acer saccharum grandidentatum ( Largetooth maple "I 63 



Acer negundo ( Boxelder) 63 



ITiignadia speciosa (Texas buckeye; Mexican buckeye) 63 



Sapindus marginatus ( Wild China tree) 64 



Rhamnus crocea ( Evergreen buckthorn ) 64 



Rhamnus purshiana (Bearberry) 64 



Zizyphus obtusifolius (Obtuseleaf zizyphus) 64 



Cereus giganteus (Giant cactus) 64 



Cereus thurberi (Thurber cactus ) 66 



Cereus schottii ( Schott cactus) 66 



Opuntia f ulgida ( Choya ) 66 



Opuntia versicolor ( Tree cactus) 66 



Opuntia si:)inosior ( Sigura) - 66 



Arbutus arizonica ( Arizona madroiia ) 66 



Arctostaphylos pungens (Manzanita) 67 



Bumelia rigida (Shittimwood) 67 



Brayodendron texanuni (Mexican persimmon) 67 



Fraxinus cuspidata ( Fringe ash) 67 



Fraxinus velutina ( Leatherleaf ash ) 68 



Chilopsis linearis ( Desert willow) 68 



Sambucus mexicana ( Mexican elder) 68 



Sambucus glauca ( Pale elder; sanco) 69 



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



Border of the United States 69 



Chamaecyiaaris (Cedar) : . 69 



Ficus (Fig) 69 



Melia azedarach ( China 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 74 



Summary of collecting stations 143 



Mammals of the Mexican Boundary Region 149 



Order Marsupialia , 150 



Family Didelphiida? 150 



Genus Didelphis 150 



Key to the Species of Didelphis found on the Boundary Line. 150 



Didelphis mesamericana texensis 150 



virginiana 153 



Order Edentata 156 



Family Dasypodidse 156 



Genus Tatu 157 



novemcinctum 157 



Order Ungulata 158 



Family Tayassuidaj 159 



Genus Tayassu 159 



angulatum 160 



sonoriense 162 



