TA i;lk of contexts 



Tage. 



T VBLE OF CONTENTS V 



List of illusteations - xi 



Organization of the International Boundary Commission .. .'. 1 



Establishment of the biological sect inn of the Survey 2 



Persons who participated in the field work of the biological section 5 



Acknowledgments 6 



Monuments and boundary sections 7 



Itinerary 8 



( ieneral character of the region explored 23 



Flora of the Mexican Boundary region 32 



List of trees of the Mexican Boundary Line , 36 



Pinus strobiformis (Mexican white pine) 36 



Pinus cembroides (Mexican pifion ) 37 



Pinus edulis ( Pifion) 37 



Pinus monophylla (Single leaf pifion ) 37 



Pinus torreyana (Torrey pine) 38 



Pinus arizonica ( Arizona pine-) 38 



Pinus ponderosa (Bull pine) 38 



Pinus mayriana (Mayr pine ) 38 



Pinus chihuahuana (Chihuahua pine) 39 



Pinus sabiniana ( Sabine pine) 39 



Pinus coulteri (Coulter pine) 39 



Pseudotsuga mucronata (Douglas spruce ) 39 



Abies concolor (White fir) 40 



Taxodium distichum (Bald cypress) 40 



Libocedrus decurrens (Incense cedar) 40 



Cupressus goveniana (Gowen cypress) 40 



Cupressus arizonica (Arizona cypress) 41 



J uniperus monosperma ( One seed juniper) 41 



Juniperus californica (California juniper) 42 



Juniperus pachyphloea (Alligator juniper) 42 



Neowashingtonia filamentosa (Fanleaf palm) 43 



Yucca treculeana (Texas Spanish bayonet) 43 



Yucca brevifolia (Schott yucca) 43 



Yucca radiosa (Desert yucca) 4.'! 



Yucca macrocarpa ( Largefruit yucca) 44 



Yucca mohavensis (Mohave yucca) 44 



Nolina bigelovii (Bigelow nolina I 44 



Juglans rupestris ( Western walnut) 44 



Hicoria pecan ( Pecan) 45 



Salix nigra (Black willow) 45 



Salix occidental is longipes (Longstalk willow i 45 



Salix amygdaloides (Almondleaf willow) 40 



Salix laevigata (Smoothleaf willow) 46 



Salix fluviatilis ( Longleaf willow) 40 



Salix argophylla i Canescent willow) 40 



Salix taxifolia (Yewleaf willow i 40 



Salix lasiolepis (Bigelow willow 1 47 



Salix nuttallii I Nut tall willow) 47 



Popuhis tremuloides (Aspen; quaking asp) 47 



v 



