61 
No native trees or bushes of any size were observed about the 
shores and wood for building purposes and fuel is very scarce. 
In the shallower parts of the lake a tall rush much like Scirpus 
lacustris is abundant and out of this the Indians make a very 
neat, boat-shaped raft called balsa, with sail also of rushes, which 
they use in navigating the smaller arms and bays, rarely going 
more than three or four miles from shore however. The 
use this boat in netting and spearing fish and in pulling up from 
Fic. 6. Balsas made of Scirpus on Like Titicaca. 
the lake bottom water- plants which they feed -to cattle picketed 
out along shore. This rather unusual fodder consists largely of 
a species of Myriophyllum and a somewhat grass-like plant, pos- 
sibly a Potamogeton, mixed with Chara and a green filamen- 
tous alga. The cattle eat these things, doubtless, from necessity 
rather than choice, but the rush above mentioned they will wade 
far out into the water to obtain, so that when feeding little more 
than their backs and heads are visible. 
