264 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 

Willughbaeya. GuaAco. | 
A genus of climbing composites, represented in Porto Rico by several species, 
some of which are known to be called ‘‘ guaco.”’ Urban describes, under the 
synonym Mikania, the new species M. pachyphylla, M. fragilis, M. odoratissima, 
and M. porosa. (Urban, Symb. 1: 463-466. ) 
Willughbaeya cordifolia. Guaco. 
A woody annual vine growing in hedges and waste places. (Stahl, 5: 115, as 
Mikania gonoclada.) 
Willughbaeya odoratissima. 
This is the plant described by Stahl as Wikania convolvulacea. Sintenis’s speci- 
men is from Maricao. (Urban, Symb. 1: 464; Stahl, 5: 116.) 
Willughbaeya porosa. GUACO DE CABRA. 
A very slender species, described by Urban (as Mikania), from the vicinity of 
Lares. To this has now been referred Stahl’s plant, described as Mikania swart- 
giana. (Urban, Symb. 1: 465; Stahl, 5: 118.) 
Willughbaeya scandens. GUACO FALSO. é 
A climbing, woody plant, found in hedges and waste places. (Stahl, 5: 117, as 
Mikania scandens.) Mikania congesta is included in this species. 
Winter cherry. See Physalis. 
Wissadula rostrata. PICHANA. 
Family Malvaceae; an annual or biennial shrub, 1 meter high, common on ine 
south coast. (Stahl, 2: 70, as Abutilon periplocifolium. ) 
Xanthium canadense. BARDANA MAYOR. 
A composite weed well known throughout eastern North America. 
Xanthium macrocarpum. BarRDANA MAYOR. 
A biennial shrub, 1 meter high, found near Bayamon. (Stahl, 6: 25.) 
Xanthosoma. YAvTIA. 
Family Araceae; in Porto Rico there are four kinds of taros, or ‘* yautias,”’ as 
they are there called. Three of them are species of Xanthosoma, a genus of 
aroids closely related to Colocasia, but having the leaves hastate—that is, the 
basal lobes are not connected behind the insertion of the stalk, as in Colocasia. 
The species of Xanthosoma are recognized as distinctively West Indian, and were. . 
- cultivated by the Caribs when the Spaniards arrived, but curiously enough the 
-taro is the only one which has retained a thoroughly native name. The Xanthoso- 
mas are known, respectively, as ‘‘ yautia blanca,”’ ‘‘ yautia amarilla,’’ and ‘“‘ yautia 
palma,”’ while the taro is called ‘‘ yautia malanga.’’ 
Xanthosoma violaceum. 
Reported from Sierra de Luquillo. 
Xanthoxylum. See Zanthoxylum. 
Ximenia americana. 
Family Olacaceae; a small tree bearing an edible drupe, of general distribution 
in the Tropics of both hemispheres, but not yet reported from Porto Rico. 
Xylosma schwaneckeanum. 
Family Flacourtiaceae; reported from Sierra de Luquillo. Urban has recently 
transferred Myroxylon schwaneckeanum to Xylosma, also Myroxylon pachyphyl- 
lum. (Urban, Symb. 1: 371.) 
Yagrume. See Didymopanax micans and Didymopanax morototont. 
Yagrume macho. See Didymopanax morototoni. 
Yagua. See Roystonea borinquena. 
The usual name applied to the royal palm in Porto Rico, but more strictly that 
of the large leaf bases used for roofs of houses and numerous other domestic pur- 
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