296 ANNUAL KEPOET SMITHSONIAN INSTITUTION, 1915. 



in the Canada de Zopilote, between Zumpanga and Mezcala, State of 

 Guerrero) contrasted with a leaf of Eysenhardtia adenosiylls Baill. 

 from Guatemala. 



1 PtcTocavpus acapulcensis Rose, shown on plate 7, is apparently 

 much more closely related to the Philippine narra. Of Pterocarpus 

 ophyUus Micheli 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 drago^ or drag- 

 on's blood tree, and P. a.phyUus (possibly identical with A. piihes- 

 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, Avliich is derived from a climbing palm, Daemonorops draco 

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

 of Socotra and the Canary Islands derived from j^ucca-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 ma}" be said of the so-called dragon's blood derived from 

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

 stance which exudes from Pterocarpus trees, called sangre de drago 

 b}^ the Spanish colonists has nothing to do with the fluorescent ex- 

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

 callj^, 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 Croton draco^ belonging to the Euph- 

 orbiaceae. To the latter the ancient Mexicans applied the name 

 ezquaJbuitl (from the Nahuatl eztli, blood, and quahmtl^ tree). It is 

 quite possible that the name tlapalezpatU (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, 

 Eysenhardtia polystachya^ the wood of which was used by the Hon. 

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

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

 Pterocarpus vtulica {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- 



