Feb. 1908.J 



103 



Saps and Exudations* 



A NEW RUBBER TREE: PALO 

 AMARILLO. 



{Euphorbia fulva, Stapf. ; Syn. E. elas- 

 tica, Altamirano and B,ose, not oj 

 Jumelle-) 

 By Otto Stapf. 



In July, 1903, Dr. Altamirano, Director 

 of the Institute Medico Nacional Mexico, 

 and Dr. J. N. Rose, Assistant Curator 

 of the National Museum, Washington, 

 published a description and illustrations* 

 of a new species of Euphorbia (E. 

 elastica) known in Mexico as El Palo 

 Aiuarillo. Prom the name, a footnote, 

 and the description of the plates, it 

 could be gathered that the plant was 

 used and recommended for the produc- 

 tion of rubber. A fuller memoir on the 

 subject by Dr. Altamiranot appeared 

 in the same year. An abstract of this 

 was published by Dr. R. EndlichJ of 

 Mexico, and the notes given below on 

 the tree and the rubber production from 

 it are taken from this article. Unfortun- 

 ately the name of Euphorbia elastica 

 was, a few months previouslj r , viz., in 

 April of the same year, given by Pro- 

 fessor Jumelle to a totally different 

 species of Euphorbia, a native of Mada- 

 gascar. The Mexican plant had there- 

 fore to receive a new name and, as 

 " Amarillo " corresponds to the Latin 

 "fulvus," I propose for it the name 

 Euphorbia fulva. Euphorbia fulva is 

 a tree 8-10 metres high, with a yellow, 

 smooth, shining bark; hence the name 

 Palo Amarillo, § that is "yellow tree." 

 It occurs in the States of Michoacau, 

 Guanajuato, Jalisco, and in the western 

 parts of the State of Mexico, usually at 

 an altitude of 1500-1900 m. The annual 

 rainfall of that area is between 550 aud 

 750 mm., and the mean annual tempera- 

 ture between 17° and 20° C. (62'5°— 68° P.). 

 The tree thrives well also on stony or 

 rocky soil. Attempts to produce rubber 

 from its latex were made in Michoacan 

 some time ago, but given up as no 

 process was known to separate the 

 rubber from the resin, which occur in 

 the proportion of 18-20 per cent, and 40 per 



*Dr F Altamirano, El Palo Amarillo (Ewkor- 

 bia elastica, Altamirano and Rose, sp. n.jv.) pp 

 1-3, tt. I-IV, (Secretaria de I omento, Coloui- 

 7. ciont Industria Instituto MeJico Nacional, Mexico, 

 1905). 



fDr. P. Altamirano, El Palo Amarilli como 

 produetor de caucho Primera memoiia ( -lexioo : 

 imprent .y fotutipia de la Seeretana do Fomeato, 

 1905). Nut seen. 



£ Der Tropenflanzer, 1906, pp. 525 -531. 



§ Tho name I'alo Amarillo is also applied to 

 Berberis pinnata, Lag., (Mahonia pinnata, Fedde), 

 and two species of Buconnia, viz., B. arboria, 

 Watts, and B. frutescens, Linn.— See Ramirez, 

 Sinon. Plant. Mex. p. 52. 



15 



cent, respectively. Recently, however, 

 Professer Lozano succeeded in separat- 

 ing completely the two substances and 

 producing very good rubber, according 

 to some, even better than " caucho 

 negro" (Central American Rubber), and 

 from the resin, an excellent varnish. 

 The process of separation has, however, 

 so far not been made public, and at the 

 time the article was written the whole 

 matter was in the experimental stage, 

 although plans for working the Palo 

 Amarillo in Michoacan were under con- 

 sideration. Since then an application 

 for a concession to establish and work 

 factories for the extraction of rubber 

 from tue tree in the States of Guerrero, 

 Jalisco, Michaocau, Guanajuato, Oaxaca, 

 Puebla, Lower California, Colima, and 

 the Territory of Tepic has been made 

 by Senor Carlos Llaguna y del Hoyo, of 

 iHichaocan.* The latex of Palo Amarillo 

 is yellowish white, thin, and does not co- 

 agulate readily. To effect this it is ex- 

 posed to the sun. If not subjected to 

 Lozano's process the product is dark 

 yellow, dough-like and neither resilient 

 nor viscous. If boiled the latex turns 

 very sticky and whitish grey. Experi- 

 mental tapping in Guanajuato and 

 Michaocan resulted in an average yield 

 of 1 lit. (l - 75 pint) of latex per tree. 

 It is recommended to proceed with the 

 tapping from the branches downwards, 

 aud to use sharp tools. If the tapping 

 is done judiciously the tree may b? ready 

 for another yield after three months, 

 and it is expected that it will stand three 

 tappings per annum for ten years. 



In Atecucario hatches or "machets" 

 (lary;e knives) are used, and the incisions « 

 are made in an oblique direction parallel 

 to each other, or in spirals. The latex 

 is collected in petroleum cans or small 

 pots. A certain portion coagulates on 

 the tree and is removed with knives. 

 It has been calculated that 100,000 trees 

 would yield 300,000 Kg. (about 291 tons) 

 latex per annum, Irom which 51,000— 

 60,000 Kg. (53-58 tons) rubber and 120,000 

 Kg, (116\ tons) resin might be obtained. 

 The price of the rubber is estimated at 

 2 pesos (about 4s.), and that of the resin 

 at 75 cms. (Is. 6d.) The scattered occur- 

 rence of the tree, however, and the 

 great distance of the areas where the 

 tree is fairly common are a considerable 

 drawback. It has therefore been pro- 

 posed to lay out plantations of the tree 

 the more so as it is easily propagated by 

 cuttings and grows fast. Large tracts 

 of waste laud might in this way be 

 made productive. A valuable by-pro- 



* Diario Oficial, dated March 8th, 1907, according 

 to an official despatch to the Foieign Office by R. 

 Tower, Envoy Extraordinary and Minister Pleni- 

 potentiary, Mexico, dated March 13th, 1907. 



