Chap. V. 
TUCSON. 
503 
close to the river and surrounded by a thick mezquite- 
wood, lies the little place of Tubac, the population of 
which are mostly Indians, amongst whom are many 
" tame " Apaches. The women and girls of this people 
sat by the road-side, staring at us with their broad, fat, 
rnongol, expressionless faces. 
The last inhabited place in the valley is Tucson. At 
that time it was the most northern of the Mexican military 
posts : having now, together with Tubac and San Xavier, 
been transferred to the United States, Santa Cruz has 
probably taken its place. We encamped a few miles 
above the town, in a pleasant part of the valley. A rapid 
brook, clear as crystal, and full of aquatic plants, fish, and 
tortoises of various kinds, flowed through a small meadow 
covered with shrubs. The meadow itself was situated at 
the foot of a steep rocky hill, with a watch-tower on the 
top, where the Mexican garrison used to keep a guard 
stationed to watch the Indians. The sides of the hill were 
so covered with cactus-columns that it might have been 
called a Saguarro-forest, could the term have been applied 
to a spot overgrown with bare trunks, without any crown 
whatever. Here I saw for the first time a small tree re- 
sembling a Genista, Spartium, or Retama. It has a green 
stem, green branches, and green twigs delicately subdi- 
vided, with only a few slight rudiments of leaves. It bears 
yellow blossoms, and pods with a single seed. This tree, 
which we often met with afterwards, and which belongs to 
the plants characteristic of the rocky deserts on the Gila, 
was called Corchi by the Mexicans ; they suck the acid 
gum which oozes from its bark to allay thirst. 1 
1 I have no doubt this tree has 
already been described, and my account 
of it above is of course not intended for 
botanists, but for those who take an 
interest in the general physiognomy of 
landscapes. 
