1630 
Parthenium argentatum (Asteraceae ), 51700. Guayule, From 
Marfa, Texas. Plants presented by Mr. R. A. Epperson. 
The guayule- Is a spreading, much-branched shrub, 
rarely as much as 3 feet in height, with small, green- 
ish, silvery gray leaves, and a profusion of small 
yellow flowers borne in loose clusters on slender 
stems. The shrub is native to a comparatively small 
area in southwestern Texas and northwestern Mexico. 
Unlike most other rubber-produoing plants, the bark 
of the guayule contains no latex, the rubber being 
in the cellular tissue of the epidermis and. to. a cer- 
tain extent in the branches and leaves. The dried 
plants are ground and the rubber is extracted by one 
of several chemical processes. Although guayule rubber 
is not of the highest grade, It has a possible future 
because the plant will grow In semi-arid regions, it 
does not suffer from light frosts after passing the 
seedling stage , and the plants may be gathered through- 
out the year. (Adapted from Commerce Reports No. 149, 
June 26, 1918. ) 
PolakoW8kia iaeaco (Cucurbitaceae), 51606. From San 
Jose, Costa Rica. Fruits presented by Mr. Oton Jim€- 
nez, chief, Department of Botany, National Museum. .'^A 
cucurbitaceous plant, the fruit of which is used as 
a green vegetable. It Is a near relative to the chay- 
ote, but the fruit is smaller, fusiform, beset with 
stiff spines at the base, and has a different flavor. 
It is one of the primitive foods of the natives of 
Costa Rica, where it grows wild in moist , shady places 
of the temperate region, and its use as a vegetable has 
been readily accepted by the Spanish. Costa Ricans. The 
fruits, about 2| inches long and l£ inches broad , hang 
from short stems and are picked while still green. 
•After removal of the basal spines the fruits are boiled 
in water, or pickled, or made into preserves. They 
are also a favorite addition to the native soups." 
(Henry Pittier. ) 
"The kinds which are cultivated contain very little 
fiber. They are used In many ways, - pickled, as a 
dessert, as a vegetable, etc., - and are always very 
popular with us. The most common method of preparation 
consists in cooking the entire fruit with some of the 
leaves. When the fruit Is cooked the skin peels off 
readily, and on pressing it with the thumb and finger 
the seed comes out easily. All that remains, with the 
exception of a little fiber, is eaten." (Jimenez.) 
