TABLE OF e'0:XTE^sTa 



Page. 



Table of contexts v 



LlST OF ILLCSTRATIOXS 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 S 



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 pineal 36 



Pinus cembroides (Mexican pinon 1 37 



IMnus edulis ( Piiion) 37 



Pinus monophylla (Single leaf pinon) 37 



Pinus torreyana (Torrey pinel 38 



Pinus arizonica ( Arizona pine) 3S 



Pinus ponderosa ( Bull pineal 3S 



Pinus mayriana (Mayr pine ^ 38 



Pinus chihuahuana ( Chihuahua pine) 39 



Pinus sabiniana ( Sabine piine^ 39 



Pinus coulteri (Coulter pine) 39 



Pseudotsuga mucronata (Douglas spruce t 39 



Abies concolor ( White fir) 40 



Taxoditmi distichum (Bald cypress) 40 



Libocedrus decurrens ( Incense cedar) 40 



Cupressus goveniana ' Gowen cypress ^ 40 



Cupressus arizonica ( Arizona cypress ) 41 



J imiperus monosperma ( One seed juniper) 41 



Juniperus californica i, California jitniper ' 42 



Juniperus pachyphlt ea (Alligator juniper) 42 



Neowashingtonia filamentosa (Fauleaf 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 



Xolina bigelovii i Bigelow nolina > 44 



Juglans rupestris (^ Western walnut ) 44 



Hicoria pecan (^ Pecan) 45 



Salix nigra i^ Black willow) 4o 



Salix occidentalis longipes (Longstalk willow ) 45 



Salix amygdaloides v Almondleaf willow) 46 



Salix h^vigata ( Smoothleaf willow * 46 



Salix fluviatilis ( Longleaf willow 46 



Salix ai-gophylla i Canescent willow) 46 



Salix taxifolia [ Yewleaf willow i 46 



Salix lasiolepis [ Bigelow willow ) 47 



Salix nuttallii i Nuttall willow) 47 



Popuius tremuloides (Aspen; quaking asp) 47 



V 



