Miscellanies. 399 



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3. Gum Ammoniacum.- — Linnaean Society, Dec. 9, 1830. — A pa- 

 per was read on the plant which yields the gum ammoniacum, by Mr. 

 David Don, Lib. L. S. — Although the gum ammoniacum has held 

 a place in the Pharmacopoeia from a very early period, yet the plant 

 itself has hitherto remained wholly unknown. It proves to be a new 

 genus, belonging to the group of Umhelliferce, named by DeCandolle 

 PeucedansiB, differing essentially from Ferula and Opopanax, in its 

 large cup-shaped epigynous disk, and in having solitary resiniferous 

 canals. The specimen was obtained, in the districts where the gum 

 ammoniacum is collected, by Lieut. Col. Wright of the Royal Engi- 

 neers, on his. way through Persia from India, and was by him pre- 

 sented, along with other dried plants to the Linnsean Society. Every 

 part of the specimen is covered by drops of a gurri, possessing all 

 the characters of gum ammoniacum, and this circumstance alone 

 would seem sufficient to remove all doubt on the subject, but Mr. 

 Don has carefully compared it with the fruit and fragments of the 

 inflorescence found intermixed with the gum in the shops, and he 

 finds them to accord in every respect, so that the plant may now be 

 considered as fully ascertained. Dioscorides derives the name Am- 

 moniacum from Ammon or Hammon, the Jupiter of the Libyans, 

 whose temple was situated in the desert of Cyrene, near to which 

 the plant was said to grow ; but as the plant is now ascertained to 

 come from the north of Persia and not from Africa, Mr. Don is dis- 

 posed to consider the name Ammoniacum or Armoniacum, as it is 

 indifferently written by ancient authors, as merely a corruption of 

 Armeniacum. We subjoin Mr. Don's essential character of the 

 genus, and some of the more important parts of the detailed de- 

 scription. 



Dorema. Discus epigynus cyathiformis. Achenia compressa, 

 marginata; costis ointermediis distinctis, filiformibus. Valleculce 

 iinivittatae. Commissura 4vittata. 



