574 A TEXT-BOOK OF BOTANY. 



to, and cultivated in, tropical and sub-tropical countries. It is 

 prepared by extracting the leaves with water. The glucosidal 

 principle indican (or mother-substance of indigo blue) undergoes 

 oxidation and the insoluble indigo blue separates out. This is the 

 commercial indigo. A similar principle is found in the wild indigo 

 (Baptisia tinctoria) of the United States and Canada; the leaves 

 of Robinia Pseud-acacia of North America ; several species of 

 Psoralea and Amorpha, as well as some other Leguminosae. It is 

 also found in other families, as in Polygonaceae, Cruciferae, Ascle- 

 piadaceae, and Apocynaceae. 



A yellow coloring principle is found in the dyer's broom 

 (Genista tinctoria) of Europe and Asia and naturalized in the 

 New England States. G. ovata of Europe yields a similar dye. 



COPAL RESINS are derived from a number of the Leguminosae : 

 American copal from Hymencca Coubaril of the West Indies and 

 South America ; Brazilian copal from H. Martiana of Rio Negro ; 

 Zanzibar or Chakazzi-copal from Trachylobium mosambicense of 

 Western Africa; Sierra -Leone copal (yellow gum, red gum) from 

 Copaiba Guibourtia of Sierra Leone; Inhambane copal from Co- 

 paiba conjugata and C. Gorskiana of Singapore, Jamaica and 

 Australia. 



A number of the LOCO-WEEDS containing principles poisonous to 

 cattle belong to the Leguminosae. The word " loco," meaning 

 crazy, is of Spanish origin, and is applied in reference to the pecu- 

 liar nervous symptoms manifested by the affected animals. The 

 plants causing greater loss than all other poisonous plants com- 

 bined and regarded as loco-plants par excellence are Aragallus 

 Lamberti and Astragalus mollissimus. Of these two Aragallus 

 Lamberti, also commonly known as rattleweed or white loco, is the 

 most poisonous and has a wide range, extending from Alaska on 

 the north down through the whole grazing region of the Great 

 Plains, where it is very abundant. Astragalus mollissimus, known 

 as purple loco, woolly loco, or Texas loco, is more limited in its 

 range. Among other plants causing heavy losses to stockmen on 

 the grazing lands of the Great Plains east of the Rocky Mountains 

 may be mentioned the following: Zygadenus elegans (Fam. Lili- 

 aceae), especially dangerous to sheep ; the larkspurs or Delphiniums 

 (Fam. Ranunculaceae), causing losses among cattle; and lupines, 



