1881. ] Botanical Notes from Tucson. 979 
name for sun-dried mud bricks, are generally but one story high, 
and have flat roofs. This kind of a house, with walls often two 
feet in thickness, is said to be much cooler in summer and warmer 
in winter than any other, and the thickness of the walls ought 
surely to keep out both heat and cold. To keep out the heat, 
however, is a much more important consideration than the cold, 
in a climate where the mercury often rises to 120° in the shade, 
and sometimes to 125°. In the summer the heat is something 
fearful to think of, but the air is so dry and so pure, that a degree of 
heat unbearable in our climate, can be easily endured in that one. 
During the summer many of the people take their cots into the 
yard, on to the sidewalk, or on the house tops, and sleep with the 
sky for a roof. In Yuma it isa common sight to see, early in 
the morning, people getting up and making their toilets in the 
Open air. 
The bricks of the houses are about twenty inches long, eight 
inches wide and three inches thick. They are fastened together 
with a mortar made of earth mixed with water, the sidewalk often 
being dug up to furnish the principal ingredient. The houses are 
built in the form of a square or oblong, with a court in the cen- 
ter, thus allowing a free circulation of air and making the house 
much cooler. The better class have a covered porch, or “ re- 
mada,” round the court, and here the people sit and work during 
the day, and sleep during the hot weather. 
There are many curious sights to be seen in and about Tucson, 
Curious at least to Eastern eyes, but it is not my intention to 
Speak of them here. During a stay of some six weeks in the 
city, I collected the plants of the immediate vicinity, and it is to 
them I shall refer at present. 
The commonest plant of all the country about Tucson is known 
_ locally as the mesquite. Under this general name there are included 
several very distinct trees, but with the same general habit, which 
are all grouped under the name of mesquite. Sometimes they are 
Scattered singly over the desert ; and sometimes they are clustered 
together in a dense thicket. The trees are low and scraggley, 
with the branches sweeping the ground on all sides. They have 
handsome acacia-like leaves, and long branches of bright yellow 
flowers, succeeded by the pods which serve some of the Indian 
tribes as food. Concealed by the leaves are myriads of thorns in - 
all stages of growth, but all hard, sharp and tough. Inattempt- 
