COOK AND COLLINS—ECONOMIC PLANTS OF PORTO RICO. 2381 
Rondeletia laevigata. See Rondeletia inermis. 
Rondeletia portoricensis. 
Family Rubiaceae; a tree attaining 20 meters, recently described from speci- 
mens obtained at numerous localities—Luquillo, Naguabo, Barranquitas, Penuelas, 
Adjuntas, and Maricao. (Urban, Symb. 1: 414.) 
Rorippa nasturtium. WATER CRESS. BERROS. 
A cruciferous herb found on banks of rivulets and in wet places. Used for 
salad. (Stahl, 2: 36.) 
Roseta. See Myroxylon buxifolium. 
Rosewood. 
A name applied to a considerable variety of tropical woods valued for hardness 
and beauty. The best is said to come from Brazil, and is yielded by Dalbergia 
nigra, a leguminous tree. Three Porto Rican trees, Cordia gerascanthus, Lino- 
ciera ligustrina, and Amyris balsamifera, have been called rosewood. 
Roucou. See Bixa orellana. 
Said to bea Carib name. Bixa was used by the indigenes to paint their skins red. 
Rourea frutescens. JUAN CALIENTE. 
Family Connaraceae; said by Bello to exist on the south coast, but not found 
by Stahl. (Stahl, 4: 56.) 
Rourea glabra. JUAN CALIENTE. 
A shrub with long flexible branches, 3 to 4 meters high, from which are made 
riding whips commonly for sale at wayside shops. The growing plant was pointed 
out to us at Coamo, and has been reported from Las Marias and Sierra de Luquillo. 
Bello calls this *‘ bejuco de garrote.”’ (Stahl, 4: 54.) 
Roystonea. ROYAL PALM. 
A genus of palms formerly referred to Oreodoxa. See species below. 
Roystonea borinquena. PorTo RICAN ROYAL PALM. YAGUA. PLATE XIII. 
Family Arecaceae; the royal palm, or ‘‘ palma real,’’ is not only the more con- 
spicuous and characteristic natural object in most parts of Porto Rico, but it 
probably exceeds the cocoanut in total economic importance. The most useful 
part is the yagua, or sheathing base of the leaf, with which a large proportion of 
the houses of the poorer classes are thatched or sided, or both. 
The royal palm is one of the wild species which has been distinctly advantaged 
by human interference in natural conditions. It is a general fact that outside the 
climbing species palms are not successful in competing with tropical forest vege- 
tation. Originally the royal palm and the ‘‘corozo’’ were probably confined to 
the more rugged slopes of the lower limestone hills, where they both still retain a 
foothold in places where the natural growth seems never to have been cleared 
away. But the vast majority of royal palms now in existence in Porto Rico stand 
on land which has been cultivated at one time or another, and where the palms 
were able to secure a foothold before the competition of other plants became too 
strong. 
The discovery of root tubercles on a young plant of this species has been noted. 
These tubercles, though small in size, are very numerous upon the smaller roots. 
In shape they are mostly oval and symmetrical. The larger are about 2 mili- 
meters in length. 
Roystonea regia. CUBAN ROYAL PALM 
This species does not occur in Porto Rico. The Porto Rican royal palm is now 
separated under the name Roystonea borinquena. 
Rubber vine. 
In Jamaica this name is applied to Cryptostegia grandiflora, one of the Asclepi- 
adaceae introduced from the East Indies, and to Forsteronia floribunda, a native 
species belonging to the Apocynaceae. 
