20 BULLETIN 1409, U. S. DEPARTMENT OF AGRICULTURE 
In the same semidesert region between the wooded zone in the 
western Pampa and the eastern slope of the Andes, perhaps the 
most common shrub is the jarilla [Larrea cuneata), which grows 
usually in a cluster with straight stems about the height of a man's 
head, with narrow, willow-like leaves which are alternate and usually 
point due north, south, east, or west. There are many other small, 
spiny, low-growing, dull-gray shrubs in the desert region. The 
cactus most common in this region is a small pear-shaped plant 8 
to 10 inches long and about 3 inches in diameter, with needle-shaped 
spines 3 to 6 inches long. It often grows in mats,, sometimes several 
acres in extent. 
The mountain regions of Argentina are generally bare of vegetation 
except far to the south where on the slopes and in the valleys are to 
be found forests of pine, beech, araucaria, cedars, and oaks. The 
semidesert region of Patagonia is much like the region of the same 
character as the western Pampa. In the north there are some 
calden, algarrobo, chanar, jarilla, and other shrubs and cactus. 
Willows grow along the streams, and in the irrigated sections in 
Kio Negro and Neuquen are the usual plantings of Lombardy poplars 
and willows for windbreaks and fuel. 
The Gran Chaco is generally a wooded region wherever there is 
sufficient moisture to support vegetation. Except for small colonies 
near railroad stations and river landings the country is unsettled. 
Among the most valuable trees of the Chaco region is quebracho 
Colorado (ScJiinopsis lorentzii), which is used for posts, railroad ties, 
tannin extract and fuel — having the same value and selling for the 
same price per ton as coal. This is the most valuable tree of 
Argentina. It is a tree of relatively slow growth, survives to a great 
age, reaches a height of 45 to 50 feet, with a trunk diameter in excep- 
tional cases of 3 feet. The trunk is fairly straight, but the branches 
are crooked and the leaves are small. The wood is exceptionally 
hard (from which it derives its name "break ax ") . It can be worked 
only with the finest steel tools and split only between the annual 
rings, as the fibers are so crossed and interwoven that it is impossible 
to split it across the grain. It is heavier than water, is a deep rich 
mahogany red in color, and contains from 15 to 25 per cent tannin. 
A large part of this valuable forest product has already been cut 
and probably not more than 50 per cent of the original supply remains. 
Quebracho bianco (Aspidospermo quebracho bianco) is another valu- 
able tree that grows in the Chaco and is used principally for fuel. 
In this region are many algarrobo trees, acacias, and other thorny 
trees and shrubs, and in the drier regions to the west are immense 
areas covered with giant cacti. 
Palo santo (Bulnesia sarmienti) is a tall-growing tree found in 
the Chaco country, but is not very plentiful. It has a wonderful 
heavy dark green, almost black, wood which is extremely hard, 
heavier than water, and contains an oily resin which exudes and 
preserves the wood. It is used in the keels of ships and as a packing 
for propellers because of its extreme hardness and durability. It is 
also used for fine cabinet work. It takes a fine polish and has a beauti- 
ful dark-green color. 
Cedro (Schinopsis Meronymi) is a magnificient tree which grows 
in the north of Argentina. It resembles the ailanthus and the wood 
is like mahogany and works easily. It is possible to obtain planks 
