260 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Uverillo. See Coccolobis laurifolia. 
Uvero. See Coccolobis uvifera, 
A tree from the coast; height. 20 to 25 feet (6 to 8 meters); diameter, 8 to 10 
inches (20 to 25 centimeters). Wood pinkish, soft; specific gravity, 0.864; not 
used. (Exp. 1857.) 
Uvillo. See Coccolobis laurifolia and C, obtusifolia, 
A tree from the coast; height, 12 to 15 feet (8.5 to 4.5 meters); diameter, 8 to 10 
inches (20 to 25 centimeters.) Wood, dark, rather hard; specific gravity, 0.964: 
used in making furniture. (Exp. 1857.) 
Valerianodes. VERBENA. 
A genus of Verbenaceae including several herbs reported from Porto Rico 
under the generic names Stachytarpha and Stachytarpheta. Stahl describes three 
species, yamaicense, cayennense, and strigosa. (6: 205-207.) 
Bello gives the name bretonica for Stachytarpha jamaicensis. 
Valerianodes dichotomum. VERBENA DE JAMAICA. 
A woody herb, 50 centimeters high; common to all parts of the island. (Stahl, 
6B: 205, as Stachytarpheta dichotoma. ) 
Valerianodes strigosum. VERBENA BLANCA, 
An herbaceous annual found along the coast, 50 centimeters high. (Stahl, 6: 
207, as Stachytarpheta strigosa. ) 
Vanilla planifolia. VaNILua, 
The * vanilla beans *’ of commerce are the pods of orchids of the genus Vanilla. 
Several species have been planted on a small scale or harvested in the wild state, 
but Vanilla planifolia, a native of Mexico and Central America, is the only spe- 
cies in general cultivation. Vanilla was used by the Aztecs and is still employed 
in Mexico for flavoring chocolate, but since its introduction to Europe in the six- 
teenth century it has been applied to many other purposes, and a large annual 
production is now required to supply the demand. Although Mexico is the orig- 
inal home of the plant, and still produces, in the State of Oaxaca, the highest 
quality of commercial vanilla, the cultural industry has received its greatest 
development in the islands of the Indian and Pacific oceans, particularly in the 
French islands of Réunion and Tahiti. Nowhere in the East has it proved possi- 
ble, however, to equal the quality of the Mexican product. Recent quotations 
show $15 per pound for the Mexican pods against $3.50 for Tahiti. a difference 
which seems to indicate that the natural conditions are not advantageous, the 
methods of cultivation bad, or the variety inferior. If experiments are to be 
undertaken in Porto Rico, no pains should be spared to secure correct propagating 
stock, together with a knowledge of the conditions and processes required for the 
production of the best grade of Mexican vanilla. Although stated to be a parasite 
by so competent an authority as Semler, vanilla is in reality merely an epiphyte or 
air-plant able to elaborate its food directly from the atmosphere. If a piece of the 
vine be hung up ina favorable situation, it will not die, but will continue to grow, 
However, the plant is not completely epiphyte, and if tied to the trunk of a tree, 
will send down roots to the ground in addition to others with which it clings to 
the bark. The character of the soil is therefore of relatively little importance in 
vanilla culture, the temperature and humidity being the chief factors. The 
extreme equability of the climate of Porto Rico is admitted by all, and is one of the 
points most insisted upon for this culture. In the matter of humidity the greatest 
variety of conditions can be found in Porto Rico, and there is every probability 
that favorable situations can be found. Too great humidity is not desirable and 
injures the aroma. 
In Mexico the Gulf region about Vera Cruz is more moist than the Pacific slope 
of Oaxaca, whence the best vanilla comes, and the East Indian and the Pacific 
