COOK—THE COCONUT PALM IN AMERICA. 325 
Warburg includes Cocos nucifera in a list of “all-tropical shore- 
plants” (Litoral-Pantropisten) that have pronounced adaptations for 
swimming (ausgepraegten Schwimmanpassungen). The adaptations 
are specified as “swimming-tissue in the husk and empty space in 
the kernel” (Schwimmgewebe im Mesocarp und Hohlraum im Endo- 
sperm) .% 
It is true that the coconut is provided with a tough, fibrous husk 
from an inch to 2 inches in thickness which enables it to remain afloat 
for a long time. There is even a layer of wax on the surface, as 
though to render it impervious to water. A contrivance better 
suited for the maritime distribution of the nut would be difficult to 
imagine, and it is not surprising that writers who approach the sub- 
ject from the standpoint of structure alone should continue to rely 
on apparently indubitable proof regarding the true habits of the plant 
in nature. 
Unfortunately there appears to be no direct evidence to support 
these deductions from the structure of the coconut and its powers of 
floating. The same general type of husk is to be found among scores 
of other related species of palms, which do not grow on seacoasts and 
are not distributed by water. That the husk of the coconut is thicker 
than that of the other related species but comports with its larger size 
and the greater danger of breakage when it falls to the ground. 
The waxy coating of the surface is also no unique character, but is to 
be found in well-nigh the whole group of palms, the small fruits of 
many inland species being far more waxy than the coconut. 
In the East Indies, where the culture of the coco palm has reached 
its highest development, nuts intended for planting are picked from 
the trees and let down carefully to avoid injury, even to the external 
coat of the husk. The breaking of this is thought to reduce mate- 
rially the chances of successful germination. To permit the husk to 
dry out or to become infected with putrefactive bacteria or fungi 
might be equally dangerous for the young plant. 
The unique habit of the coconut of preserving a store of water in an 
interior cavity of the seed is in itself an indication that the species 
was native in some relatively dry interior region where the regular 
supply of moisture from external sources would not suffice for ger- 
mination. These extensive provisions for water storage would seem 
superfluous in a maritime plant able to draw moisture from sandy 
beaches wet twice a day with tidal brine. The distance to perma- 
nent moisture on a sandy ocean beach is very short; in fact, the 
sand is never really dry at all except at the surface. For a plant able 
to thrive on a salt solution, a covering of an inch or two of sand 
« Warburg, O., Einige Bemerkungen Ueber Die Litoral-Pantropisten, Annales du 
Jardin Botanique de Buitenzorg. Supplement II, p. 133. 1898. 
