312 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
mankind, and are much more abundant in inhabited regions than in 
the undisturbed forest. 
These partially domesticated palms take advantage of the clearings 
made for the planting of corn, cassava, and other crops, and repay 
this indirect assistance by their fruits or other parts sufficiently useful 
to cause them to be tolerated, if not actually prized. Some of these 
voluntary camp followers of primitive agriculture are of distinct 
importance, so much so that they would undoubtedly be cultivated 
if they did not grow spontaneously without the need of direct assist- 
ance. Some of them are worthy of much wider consideration in 
tropical agriculture than they now receive. 
The royal palm of Porto Rico (Roystonea borinquena) is a tree of 
much importance to the natives of the island, a large proportion of 
their houses being roofed with the tough sheaths of the leaves of this 
palm, known in the island as ‘‘yagua.”’? While the leaves are alive 
the sheaths form complete cylinders 4 or 5 feet long, but when the 
leaves fall the sheaths split down one side and are then cut off and 
flattened out to form large leathery shingles. The side walls are 
often made of the same material or from the hard surface layer of 
the trunk of the same plam, split up into board-like strips. 
The fruits of the royal palm are small and are not eaten by man, 
but they have an oily flesh much relished by the pigs, so that the 
palms are generally welcomed in the pastures, where they are vastly 
more abundant than on lands where the forest is allowed to grow. 
It is claimed that the fruits dropped by each adult palm will keep a 
pig in good condition without any other food than grass. There 
‘an be no doubt that the royal palm is a more important species in 
Porto Rico than the coconut itself and that it is worthy of much 
wider consideration in tropical agriculture. 
The American wine palm, Acrocomia, is found in all parts of the 
American tropics, from Paraguay on the south to Porto Rico, Cuba, 
and Mexico on the north. Whether this wide distribution is due to 
natural agencies or to buman assistance is not known, Several 
species of Acrocomia have been described from different countries, 
but their characters are not very distinctive, and they may prove 
to be only local variations of a single species. 
In most places the Acrocomia palms are found only about human 
habitations or in lands that have been cleared for agricultural pur- 
poses, as Indicated by Wallace for the Para region of Brazil. 
The stem of this tree is about 40 feet high, strong, smooth and ringed. The leaves 
are rather large, terminal and drooping. ‘The leaflets are long and narrow, and spread 
irregularly from the midrib, every part of which is very spiny. The sheathing bases 
of the leaf-stalks are persistent on the upper part of the stem, and in young trees clothe 
it down to the ground. 
The spadices grow irom among the leaves, erect or somewhat drooping, and are 
simply branched. The spathes are woody, persistent and clothed with spines. The 
