— 7 
eee a 
- 
thich yields the Gum Ammoniacum. | 601 
with the gum in the shops, and I find them to agree in every 
particular. The name applied to the plant by Dioscorides is 
already preoccupied by another genus of Umbellifere ; and 
that of Pliny is scarcely unexceptionable, as originating in a 
mistake, Metopium having been used by some ancient authors 
to denote the Galbanum, and by others the gum Arabic tree ; 
but most writers seem to agree in considering it the appella- 
tion of an ointment, or some oleaginous substance, rather than 
of a plant. To avoid any confusion, and as the plant proves to 
be a new genus, I propose to call it Dorema, from the Greek 
word dogenua, a gift or benefit; not that I consider the Ammo- 
niacum plant as pre-eminently deserving that title, but the name 
is at least a short one, and agreeable to the ear,— considerations 
not to be overlooked in nomenclature. I shall now proceed to 
give the essential character and a detailed description of the 
genus. 
DOREMA. 
| Syst. Linn. Pentannria DIGYNIA. 
Ord. Nat. UMBELLIFERZE. Juss. "Trib. vii. PEUCEDANEx. 
DeCand. 
Cuar. Essent. Discus epigynus cyathiformis, Achenia com- 
Psy 
pressa, marginata: costis 3 intermediis distinctis, filiformi- 
bus. Vallecule univittate. Commissura 4-vittata. 
Descr. Flores lanugini immersi, sessiles! Calycis margo 5- 
dentatus: dentibus ovatis, acutis, membranaceis, exiguis. 
Petala 5, ovata, acumine inflexo. Stamina 5, citò ca- 
duca: filamenta: complanata, basi dilatata: anthere in- 
cumbentes, biloculares: loculis longitudinaliter dehiscen- 
tibus, basi solutis, parüm divergentibus. Ovaria subte- 
retia, lineis 6 utrinque exarata: disco epigyno amplo, car- 
4u 2 | noso, 
