304 PLANTS NOV^ THUEBERIAIs-T;. 



" At San Felipe, a miserable Indian village, the country begins to put on a barren 

 aspect, and oaks and other trees are no longer met with. The sterile table-lands bear 

 only stunted Mezquit, Larrea, and other plants characteristic of the dry North-Mexican 

 flora. At this place a new Zizyphis, with a very large and woody fruit, was collected. 

 This was also sent home by Dr. Parry, and will be described by Dr. Torrey in the forth- 

 coming account of that gentleman's collections. A plant, which proves to be a new 

 genus in Eriogoneae, a new Porophyllum, Thamnosma montanum, Torr.,* and Simmond- 

 sia, Nutt., were also found in the same locality. 



" The desert was crossed in the night, to avoid the heat of the sun, and no opportu- 

 nity was afforded for noticing its scanty vegetation. The Colorado River, near the 

 junction of the Gila, presents little variety as to the vegetation, which is chiefly of Wil- 

 lows, Cotton-wood, Mezquit, a few species of Baccharis, and Tessaria horealis. The lat- 

 ter plant is exceedingly abundant. The quarters at Fort Yuma were built of frames 

 of poles, covered with the long and straight stems of the Tessaria; beneath this 

 shelter the tents were pitched, and protection was thus afforded from the otherwise 

 insupportable sun. 



" The distance from the confluence of the Gila and Colorado to the Pimo Villages is 

 about two hundred miles. The valley of the Gila, the general direction of which is 

 followed by the road, is narrow, and bordered by high table-lands, which sometimes 

 extend quite to the margin of the river. Isolated ranges of rugged mountains, without 

 trees or verdure, are seen in all directions, and the whole region has a desert-like char- 

 acter. The route is almost entirely destitute of grass ; and the only food for ani- 

 mals is the pulpy pods of the Mezquit (Algarobia glandulosa). These at the season 

 of our journey (June) were in perfection ; and the animals belonging to the party not 

 only subsisted, but really improved in condition, during the time it was almost their 

 sole food. Among the new plants furnished by this region is a curious Dalea, a very 

 spinose shrub of four or five feet in height, with light greenish bark and deep indigo- 

 blue flowers. Another shrubby species, Dalea Emoryi, which was mentioned by 

 Dr. Torrey in Colonel Emory's Report, but not characterized, owing to the want of 

 sufficient materials, grew in the ravines. A singular parasite was observed upon some 

 specimens, which proves to be a new species of Pilostyles. In the bottom near Indepen- 

 dence Rock (Johnston's Report), a remarkable new genus in Loasacese (Petaloni/x) 

 was discovered. Along the margins of the river several Cyperacese, yet unexamined, 



* This plant, which was imperfectly characterized, from a poar specimen, in Fremont's Second' Report 

 proves to be nearly, if not wholly, congeneric with the Rutosma Texanum, Gray, Gen. PI. t. 155, an herba- 

 ceous, Texan and North-Mexican, truly Rutaceous plant, which was published considerably later. 



