296 ANNUAL EEPOET SMITHSONIAN INSTITUTION, 1915, 



in the Cafiada de Zopilote, between Ziimpanga and Mezcala, State of 

 Guerrero) contrasted with a leaf of Eysenhardtia adenostylis Baill. 

 from Guatemala. 



'\ Pterocarpus acapulcensis Rose, shown on plate 7, is apparently 

 much more closely related to the Philippine narra. Of Pterocarpus 

 ophyllus Michel i the leaves have never been described. It is inter- 

 esting to note that the common names of both these species suggest 

 the red, bloodlike exudation which flows from wounds made in the 

 trees. Pterocarpus acapulcensis is locally known as clrago^ or drag- 

 on's blood tree, and P. aphyllus (possibly identical with A. pubes- 

 cens) is called llora-sangre^ from the fact that the tree weeps tears 

 of blood. This substance, which has been called " dragon's blood," 

 must not be confused with the dragon's blood of Sumatra and Bor- 

 neo, which is derived from a climbing palm, Daemonorops draco 

 (closelj^ allied to the genus Calamus), nor with the dragon's bloods 

 of Socotra and the Canary Islands derived from yucca-like trees of 

 the genus Dracaena. Its affinity is rather with the substance called 

 gum kino exuded by Pterocarpus marsupium of India and Cejdon; 

 and the same may be said of the so-called dragon's blood derived from 

 Pterocarpus officincdis. One thing is certain: The red, gummy sub- 

 stance which exudes from Pterocarpus trees, called sangre de drago 

 by the Spanish colonists has nothing to do with the fluorescent ex- 

 tract obtained from the wood. Several plants, quite distinct botani- 

 cally, are known in Mexico as sangre de drago, or sangregrado. In 

 addition to species of the leguminous genus Pterocarpus may be men- 

 tioned Jatropha spathulata and Groton draco^ belonging to the Euph- 

 orbiaceae. To the latter the ancient Mexicans applied the name 

 ezquahuitl (from the Nahuatl eztli^ blood, and quahuitl^ tree). It is 

 quite possible that the name tlo.palezpatli (blood-red-tincture medi- 

 cine) may have been applied to a species of Pterocarpus; but without 

 a description of the tree or a figure, it is impossible to determine this 

 definitely. 



SUMMARY. 



Lignum nephriticum, celebrated throughout Europe in the sixteenth 

 and seventeenth centuries for its diuretic properties, but chiefly re- 

 markable for the fluorescent properties of its infusion, comes from 

 two distinct sources: (1) From a Mexican shrub or small tree, 

 Eysenlmrdtia polystacJiya^ the wood of which was used by the Hon. 

 Eobert Boyle (1663) in his well-known experiments on the fluo- 

 rescence of light; (2) from a large tree of the Philippine Islands, 

 Pterocarpus indica {Pterocarpus pallida Blanco), the wood of which, 

 described by Kircher (1646) and Johan Bauhin (1650), was at one 

 time commonly made into cups by the natives of southern Luzon. 

 It is possible that cups were also made from allied species of Ptero- 



