FOOD IN THE TROPICS 
91 
like that of a walnut. The nuts are obtained by breaking open 
this outer covering. In all cases they should be boiled or roasted. 
Vines bearing edible fruits occur along many shores. In- 
cluded in these are forms of the grape, gourd, and melon. One 
common example is the strainer vine which bears elongated 
green fruits that are edible when half ripe provided they 
are cooked. The tender shoots, leaves, and flowers of this vine 
also are edible. The so-called balsam vine has rough, yellow 
fruits about 6 inches long of varying form and with reddish 
pulp that may be eaten. 
The purslane, previously mentioned as a source of moisture 
in the discussion of water on Islands (p. 33), is also edible in 
the form of greens. 
Another plant found on or near the shore is the Polynesian 
arrowroot (Fig. 20), which has a potato-like underground tuber 
that can be eaten after it has been boiled or roasted but which 
must not be consumed in its raw state as it contains poisonous 
elements that are destroyed by cooking. 
If you have the misfortune to land along a shore bordered 
by mangrove swamps do not waste your time trying to fight 
your way through or looking for food in them. Try and work 
your way along the coast to a better beach or more open type 
of vegetation. In some cases a few screw pines may be found 
growing in such swamps and there are ferns that may be eaten 
as greens, but otherwise mangrove swamps have little plant 
food. Of course, if you find yourself in such a place make the 
best of it and try to get to the coast as quickly as possible. 
