Miscellanies. 399 
The collections are arranged according to any system, that may 
be preferred. Collections will be furnished of every species in 
larger number and size, and of rich crystallizations, and of rare and 
precious minerals as may be desired according to 4 price that may 
be agreed on. 
Catalogues (raisonnés,) of the magazine of minerals and of rocks 
and ere are furnished gratis. (Forwarded to the Editor and 
inserted by desire 
3. Gum Ammoniacum.—Linnexan 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 Pharmacopeeia 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 Umbellifere, named by DeCandolle 
Peucedanee, differing essentially from Ferula and Opopanac, 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 Linnzan Society. Every 
part of the specimen is covered by drops of a gum, 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 3intermediis distinctis, filiformibus. Vallecule 
univittate. Commissura 4vittata. c 
