January i, 1910.] 



THE INDIA RUBBER WORLD 



115 



The Guayule Rubber Situation. 



By Francis E. Lloyd* 



THE history of the guayule industry attaches to itself some- 

 thing of the dramatic interest associated, in the lay mind, 

 with gold mining. And in effect sudden economic dis- 

 covery is followed by a rush for possession. A steady and swift 

 rise in values make a few rich, while those with a tardy appreci- 

 ation of the importance of the discovery fail to have "luck." 

 When it is seen that the field is limited, the fight for occupancy- 

 begins. And all this centers about a small woody plant thought, 

 up to a few years ago, to be worthless save for fuel, and what 

 meager comfort the gastronomically insistent goat could find in 

 munching the young shoots. 



The plant in question was discovered to botanical science, in 

 1852, by Dr. Bigelow when, attached to the Mexican Boundary 

 Survey, he was collecting in the region of "Escondido creek" 

 in southwestern Texas. The material, which consisted of a 

 single sprig in summer foliage and flower, was later, in 1859, 

 described by the late Professor Asa Gray under the name Par- 

 thenium argentatum, the specific name referring to the silvery 

 luster due to the closely set, air-containing hairs which cover the 

 surface. 



But while the scene of the discovery lies within the United 

 States, to which the guayule industry has quite recently ex- 

 tended, it was on the other side of the Rio Grande that the 

 guayule made its debut as an economic force. In Mexico its 

 place in primitive life without doubt antedates recorded history, 

 as playing with a rubber ball, made of "gum" extracted, by 

 mastication, from the guayule, was early indulged in among the 

 indigenes. If these folk used a rubber ball soon after the con- 

 quest of Mexico, they probably did so before. It is interesting 

 to know, in this connection, that one of the early attempts to get 

 a sufficient supply of the rubber for examination was made by- 

 organizing a chewing "bee," but we are told that an essay to 

 apply the method to the production of the crude rubber on a 

 larger scale was rendered abortive by lockjaw! Furthermore, 

 the name "guayule" has been referred to Aztec origin, and it 

 seems not wholly gratuitous to regard the etymological evidence 

 as of some, though admittedly equivocal, value. 



The Plant Described. 

 The guayule is a woody shrub of spreading habit. When 

 grown without accident, it makes a much-branched bush. If 

 the branches die away at the base, a distinctly tree-like form i« 

 assumed. Large plants may acquire a spread, or a height, of a 

 meter or more, but such individuals are of advanced age, 

 probably not less than 40 to 50 years, and, in consequence on the 

 harvesting of the plant for the manufacture of rubber, they are 

 getting rapidly fewer in number each year. The average plant 

 taking the whole into account, was estimated by Endlich in 1904 

 to have a weight of about 500 grams, and my own observations 

 indicate the approximate correctness of this. The small leaves 

 are greenish, silvery gray, as also are the younger twigs, where, 

 as the age of the axis advances, give way to light and then to 

 dark, ashy gray. The natives of the guayule regions think to 

 identify different kinds of guayule by the color of the bark, 

 or by the color of the leaves. The distinctions do not bear 

 investigation. The practical collector, however, distinguishes 

 between "macho" and "embra" guayule. The former has fewer 

 and stouter twigs than the latter. None of these distinctions 

 appear, however, to correspond to certain racial, if not specific, 

 differences which I have observed to obtain, but which appear 

 to have little economic bearing. 



The winter appearance cf the plant is strikingly different from 

 its summer appearance. In winter the leaves, save those form- 

 ing small clusters at the tips of the twigs, have fallen, leaving 

 these bare. In summer the new growths are clothed with leaves 

 of maximum size, in which the green color is more apparent 

 At this time also the flowers are borne in loose clusters on 

 slender stems and crown the plant with a profusion of small, pale 

 yellow blossoms. These are arranged in heads, each head re- 

 sembling a small daisy and capable of forming, at most, five 

 seeds. Usually some of these do not develop. A curious man- 

 ner of development results in the association with the "seed" 

 of a large amount of chaff, so that, if "seed" is collected, only a 

 very small proportion of the whole is true seed. Only a small 

 percentage of the seed is viable — discouragingly small, in fact, 

 were it not for the generally lavish hand of nature. If, despite 

 the apparently small numbers produced, all the seeds which 

 actually germinate in the field could survive, there would fre- 

 quently be many more guayule plants than could find room to 

 develop. This has been observed by me to be the case in some 

 regions, while others have shown quite the opposite condition. 

 The inference from this is that no sweeping statement as to 

 the rate at which guayule will reproduce itself from seed in 

 the field may be made. It may be within the ability of a careful 

 observer to state at what rate new plants are taking the place 

 of old, and therefore what the probable stand will be in <i given 

 number of years, for a particular and restricted locality. The 

 comment is naturally forthcoming that there has been a good 

 deal of gratuitous guesswork, more or less influenced by per- 

 sonal interest, as to the rate of rehabilitation of a guayule 



"Professor of botany, Alabama Polytechnic Institute; late director depart- 

 ment of investigation of Continental-Mexican Rubber Co. 



The Guayule Plant — Usual Habit. 



[From The India Kchber World. July i, 1905. Compare cut on a follow 

 ing page.] 



