71 



REMARKS ON A NEW PLANT RICH IN TANNIN. 

 By Charles Moore, f.l.s., &c. 



[Read before the Royal Society of N.S.W., June 4, 1890.'] 



In a letter lately addressed by me to the newspapers, I gave a 

 few details regarding an American plant which possesses to a large 

 degree, tanning properties. There seems, however, from what 

 has since appeared in the press and from private communications, 

 that more information relative to this plant is required. It is 

 therefore with that object that I now venture very briefly to 

 address you on the subject. The plant in question, Rumex 

 hymenosepalus (Torrey), belongs to the natural family Polygonacese 

 many members of which are rich in furnishing large supplies of 

 oxalic acid, while some yield strong purgative properties, but in 

 addition to these qualities, the prevailing characteristic of the 

 genus Rumex is that of astringency. We might therefore natur- 

 ally expect to find in some of the species the tanning principle 

 more or less developed. It was not, however, so far as I have 

 been able to learn, till 1868 that this principle . was known to 

 reside in the root stock to any great extent. In that year a 

 package of the roots was sent from Texas to the Agricultural 

 Department at Washington, accompanied by a letter stating that 

 by analysis they were found to yield 32 per cent, of tannin. 

 Curiously enough this letter was lost sight of till 1878, when fresh 

 roots were reported on by the Commissioner of Agriculture. 



In the American Journal of Pharmacy of 1876, p. 42, this 

 plant is referred to as having been sent from St. Antonia as 

 Indian roots or Yerba del Indio or Raiz del Indio. The root is 

 described as consisting of heavy globular or fusiform pieces, about 

 6 inches long, and from 1 to 3 inches in diameter. When fresh 

 it is externally of a reddish-brown colour, and internally varies 

 from a bright to a yellowish-brown. The roots are said to be 

 produced in clusters in a manner similar to small potatoes, and 

 grow near the surface of the ground. The plant seems to have a 

 wide range in a natural state. It has been found in many parts 

 of Mexico, where it is said to have been used for tanning purposes 

 for over two centuries. It is abundant in Texas and in South 

 Western America. The stem and leaves are acid, due to the 

 presence of oxalic acid, and are in consequence occasionally used 

 in California and Utah for culinary purposes. Several analyses 

 of this plant have been furnished, and these vary very much, but 

 under favourable conditions the roots are said to yield 37 per 



