COOK AND COLLINS—-ECONOMIC PLANTS OF PORTO RICO. 167 
Another objection to indigo has been the injurious effect of the manufacturing 
processes upon the health of the operatives; but it would probably not be difficult 
at this time to provide machinery for stirring the tanks of fermenting indigo 
and also for handling and sacking the finished product. 
Inga laurina. GuamA. 
Family Mimosaceae; a tree probably introduced, 30 to 50 feet (9 to 15 meters) 
high. The leaves usually with four leaflets. The flower clusters are longer and 
the stamens much shorter than in other members of this genus. 
As a shade tree for coffee this species is second in importance only to the 
“onava’’ (I.vera). Specimens growing at Isolina were found in some cases at 
least to have tubercles on the roots. 
According to Guerin, this tree is one of those employed in the cacao culture of 
Guadeloupe in making hedges or windbreaks which are planted across the direc- 
tion of the prevailing winds at distances of 100 meters. Such hedges are used at 
elevations where permanent shade is thought not to be required, but where pro- 
tection from the wind is necessary. In Venezuela and Colombia this is one of the 
favorite species for coffee shade. As a possible objection to it may be noted the 
report that it is susceptible to the disease called ** mancha de hierro,’’ or ‘* iron 
rust,’’ which has been very destructive to coffee, especially in overshaded plan- 
tations. , 
In Colombia, Saenz recommends the planting of this species at 10 meters where 
the temperature does not exceed 21° C.; in hotter regions a distance of 10 meters 
is advised. (Bull. 25, Division of Botany, U.S. Dept. Agr., p. 62.) 
Reported from Utuado. 
Inga vera. GUAVA. 
A tree 30 to 50 feet (9 to 15 meters) high, producing round clusters of white 
flowers with very long stamens. Asa shade tree for coffee this seems to be the 
favorite species in Porto Rico, with the related Inga laurina, or guama, second. 
Both grow much less rapidly than the bucare (Erythrina), but are less liable to 
injury by hurricanes. In well-kept plantations the lower branches are trimmed 
out and the upper form an even layer of rather open foliage. But even where 
this amount of care is taken the shade is usually still too thick for the coffee to 
make normally vigorous growth, and the crop would probably be improved by the 
removal of alternate trees, so as to increase the distances to 30 or 40 feet. 
The name of this tree is likely to be confused by the visitor with that of Psidiwm 
guajava, the well-known tropical fruit called guava in English, but by the Porto 
Ricans more correctly termed guayava. (Bull. 25, Division of Botany, U. S. 
Dept. Agr., p. 63.) 
Tubercles were also observed on the roots of this species at Isolina. 
Grosourdy (2: 386) describes the wood as strong and resistant, used only for 
the making of charcoal and for fuel. He gives the specific gravity as 0.505. This 
author is certainly in error in giving this species the native name of ‘* guama.”’ 
Ink berry. See Randia aculeata. 
Inodes causiarum. Porto RICAN HAT PALM. YARAY. 
Family Sabalaceae. The most conspicuous difference between the present 
genus and Sabal is the fact that the former produces an upright trunk while 
the latter has only what might be called an underground rootstock. Although 
such a distinction is quite artificial, both groups of species begin life with a 
creeping axis which becomes erect in one and remains horizontal in the other. A 
much more important difference is to be found in the leaves which in Inodes have 
secured strength by the development of a midrib, a tendency early abandoned by 
Sabal, in which the midrib is rudimentary and the middle of the leaf is the 
weakest part. The leaves of Sabal are adapted for standing erect, and avoid 
