STANDLEY TREES AND SHRUBS OF MEXICO. 599 



1. Euphorbia longecornuta S. Wats. Proc. Amer. Acad. 25: 161. 1890. 

 Nuevo Leon; type from Sierra de la Silla, near Monterrey. 



Stems very thick and woody below, 20 cm. high, densely branched, minutely 

 puberulent ; leaves very nximerous. oblong or elliptic, acute or acutish, very 

 short-petiolate ; glands with long-attenuate horns. 



2. Euphorbia fulva Stapf, Kew Bull. 1907: 294. 1907. 



Euphorbia elastica Alt. & Rose, El Palo Amarillo 1. pi. 1-Jf. 1905. Not E. 

 elastica Jumelle, 1905. 



Eupliorhiodendron fulvmn Millsp. Field IMus. Bot. 2: 305. 1909. 



Jalisco and Guanajuato to Oaxaca. 



Tree, 8 to 10 meters high, with smooth yellow bark ; leaves 3 to 6 cm. long, 

 1 to 4 cm. wide, glabrous above or nearly so, densely pubescent beneath ; flow- 

 ering branches usually leafless, forming a 4 or 5-rayed umbel ; involucre 

 densely toraentose ; capsule glabrous. Generally known as " palo amarillo " ; 

 " palo Colorado,' " palo de cucaracha " (Oaxaca, Reko). 



This tree is of some importance as a source of rubber. The latex is thin 

 and yellowish white and does not coagulate readily. When dried it is a 

 doughlike, dark yellow substance. By tapping, about a liter of the latex may 

 be obtained from a tree. The greatest difficulty in development of the tree 

 as a source of rubber is found in the separation of the rubber from the resin, 

 the amount of the former being 18 to 20 per cent and of the latter 40 per cent. 

 The resin is said to make an excellent varnish. A good drying oil, suitable 

 for varnish, has been extracted from the seeds.^ 



3. Euphorbia calyculata H. B. K. Nov. Gen. & Sp. 2: 59. 1817. 

 Tithynialvs caJyculatus Klotzsch, Abb. Akad. Berlin 1860: 81. 1860. 

 Euphorbiodendron calyculatum Millsp. Field Mus. Bot. 2: 305. 1909. 

 Michoacan and Guanajuato ; type from Lake Patzcuaro, MichoacS,n. 

 Shrub of small tree, glabrous throughout, the branches densely leafly ; leaves 



oblanceolate, often very narrowly so, acute or obtuse, pale green ; involucres 

 in broad leafy umbels, the bracts suborbicular, whitish or tinged with red, 

 apiculate. " Chupire," " chupiri," " chupireni " (MichoacSn, Tarascan, "that 

 which burns"); " tencuanete " or "tenquanete" {Ramirez). 



The seeds are said to contain 30 per cent of oil, which has purgative proper- 

 ties similar to those of croton oil. The milky juice of the stems causes blisters 

 upon the skin and painful inflamation. This species is said to yield a kind 

 of rubber much inferior to that obtained fi-om E. fulva. The plant is 

 discussed by Hernandez ' in a chapter entitled " De Chupiri, sen Charapeti, 

 aquam rubeo colore tingenti Arcano Venerei morbi." He states that the 

 inhabitants of Michoacan employed the plant as a remedy for venereal diseases 

 and other affections. 



4. Euphorbia elata T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 55. 1914. 

 Known only from the type locality, Fincu Irlanda, Chiapas. 



Glabrous tree, 7 meters high ; leaves oblanceolate, about 8 cm. wide ; obtuse 

 or acutish ; cymes naked, long-pedunculate ; involucres about 9 mm. broad, the 

 lobes lacerate; ovary glabrous. 



^See F. Altamirano. El Palo Amnrillo. vv>. 1-3. nl. 1-',. Mex'co. 1905; Al- 

 tamirano. El palo amarillo como productor de caucho, Mexico, 1905 ; Otto Stapf, 

 A new rubber tree; palo amarillo, Kew Bull. 1907: 294-296. 1907. 



* Thesaurus 120. 1651. 



