TABLE OF 00:tfTEIi5"Ta 



Page. 



Table of contents .- v 



List of illustrations xi 



Organization of the International Boundary Commission 1 



Establishment of the biological section 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 



General 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 pinon) 37 



Pinus edulis (Piiion) 37 



Pinus monophylla (Single leaf piflon) ....'.. 37 



Pinus torreyana (Torrey pine) 38 



i;inus 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 eonoolor (White flr) .~ 40 



Taxodium distichum (Bald cypress) 40 



Libocedrus decurrens (Incense cedar) 40 



Cupressus goveniana (Gowen cypress) 40 



Cupressus arizonica (Arizona cypress) ■. 41 



Juniperus monosperma(One seed juniper) 41 



Juniperus californica (California juniper) 42 



.Juniperus pachyphloea (Alligator juniper) 42 



Neo washingtonia fllamentosa ( Fanleaf palm ) 43 



Yucca treculeana (Texas Spanish bayonet) 43 



Yucca brevifolia (Schott yucca) 43 



Yucca radiosa (Desert yucca) 43 



Yucca macrocarpa (Largefruit yucca) 44 



Yucca mohavensis (Mohave yucca) , 44 



Nolina bigelovii (Bigelow nolina) 44 



Juglans rupestris ( Western walnut) 44 



Hicoria pecan (Pecan) 45 



Salix nigra (Black willow) 45 



Salix occidentalis longipes (Longstalk willow) 45 



Salix amygdaloides ( Almohdleaf willow) 46 



Salix laevigata (Smoothleaf willow) 46 



Salix fluviatilis (Longleaf willow) 46 



Salix argophylla (Canescent willow) 46 



Salix taxifolia (Yewleaf willow) 46 



Salix lasiolepis (Bigelow willow) 47 



Salix nuttallii (Nuttall willow) ' 47 



Populus tremuloides (Aspen; (juaking asp) _ 47 



V 



