44 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



of country. The largest trees- were 5 meters (16.4 feet) in height, 

 iind were often much branched. Its range on the Boundary, west of 

 El Paso, is between Monuments Nos. 1 and 64. (See Plate V, fig. 1.) 



YUCCA MACROCARPA (Torrey) Coville. 

 LARGEFRUIT YTICCA. 



This is the tree yucca of canyons in southwestern Texas. 



YUCCA MOHAVENSIS Sargent. 

 MOHAVE YUCCA. 



This species was found in the <;oast region west of the Colorado 

 Desert. 



NOLINA BIGELOVII Watson. 

 BIGELOW NOLINA. 



This species was found in all of the narrow desert ranges from the 

 Tule to the Gila Mountains, east of the Colorado River. The largest 

 individual seen was near si spring or tank of water in a canyon of a 

 hitherto nameless range of mountains between the Tule and Ijechu- 

 guilla ranges, but a little farther north, wholly in Arizona, which I 

 have designated as the Granite Mountains. This example was about 

 ?• meters in circumference of the naked caudex, and 8 meters in 

 height. Other specimens seen in the Gila Mountains were nearly or 

 quite as large, and not infrequently divided above into several 

 branches. The size of this plant, as usually quoted from the label 

 of Schott's type specimen (" Stem 6 feet high and 2 to 3 feet in diam- 

 eter"), is quite misleading; and botanists are surprised to find it a 

 tree of goodly dimensions — larger, in fact, than any yucca of the 

 boundary region. 



JUGLANS RUPESTRIS Engelmann. 

 WESTEEN WALNUT. 



The range of the walnut, on the Boundary Line, extends from the 

 Dog Mountains (Monument No. 55) to the Pajaritos Mountains, per- 

 haps as far as Monument No. 138. Specimens were collected at Dog 

 Spring arid Cloverdale, New Mexico; on Cajon Bonito Creek, Chi- 

 huahua; in the San Jose, Santa Cruz, and Pajaritos mountains, So- 

 nora, and in the Mule, Huachuca, and Patagonia mountains, and on 

 the San Pedro River, in Arizona. The species is also of common 

 occurrence on the headwaters of the Verde River, in central Arizona. 

 The town of Nogales received its name from the grove of walnuts 

 which occupied the present site of the city at the time of the' old sur- 

 vey of the Mexican Boundary, under Major Emory. There are still 

 many fine walnuts in the vicinity of the town and along the neighbor- 

 ing Santa. Cruz River. One of these trees, of which Mr. D. R. Payne, . 



