APIACEiE. 331 



Dorema. — Don. 



Disk epigynous, cup-shaped. Fruit slightly compressed from the back, edged; with 3 

 distinct, filiform, primary ridges near the middle, and alternating with them 4 obtuse 

 secondary ridges ; the whole tomentose. Vittse, 1 to each secondary ridge, 1 to each 

 primary marginal ridge, and 4 to the commissure, of which 2 are very small. 



This genus was instituted by Mr. Don (Trans. Linn. Soc, xvi. 599), on 

 specimens of a plant collected in Persia by Col. Wright, as that affording the 

 Gum Ammoniacum. It differs from Ferula in its sessile flowers buried in 

 wool, in its cup-shaped disk, and the single vitta to the ridges. 



D. ammoniacum, Don. — The only species. 



Don, Trans. Linn. Soc, xvi. 599 ; Pereira, Mat. Med. ii. 489 ; Lindley, 

 Fl. Med. 47 ; Royle, Mat. Med. 412. 



Description. — Root perennial, large. Stems 7 — 9 feet high, and about four inches in 

 circumference at base, clothed with a glandular down (Don), smooth (Fontannier), glau- 

 cous, resembling opoponax. Leaves large, petiolate, somewhat 2-pinnate. Pinnae in 3 

 pairs, each pair somewhat remote. Leaflets inciso-pinnatifid, with oblong,, mucronulate, 

 entire, or slightly -lobed segments, coriaceous. Petiole sheathing at base, large, tomen- 

 tose. Umbels proliferous, racemose ; partial umbels globose, on short pedicels, usually 

 arranged in a spiked form. General and partial involucre wanting. Flowers sessile, im- 

 mersed in wool. Petals white, ovate, apex inflected. Margin of calyx with 5 minute, acute, 

 membranous teeth. Disk large, cup-shaped, fleshy. Stamens and styles yellow, the latter 

 complanate, recurved at apex. Stigmas truncate. Ovary very woolly. Fruit elliptical, 

 compressed, with a broad, flat edge. Mericarps with 3 distinct, filiform, primary, dorsal 

 ridges, and, alternating with them, 4 obtuse, secondary ridges. Vittae, 1 beneath each 

 secondary ridge, 1 beneath each primary marginal ridge, 2 on each side of the suture of 

 the commissure, the exterior being very small. 



This description is condensed from those of Don, Lindley, and Fontannier, 

 the latter of whom states that Gum Ammoniacum exudes naturally from the 

 axils of the umbels and the tumid extremities of the peduncles (Meratand De 

 Lens, Diet. i. 252). The plant is a native of many parts of Persia, in dry 

 plains and gravelly soil, where it is exposed to an ardent sun. 



Although there seems now no doubt as to this species being the source of 

 the Asiatic Gum Ammoniacum, it is also certain that an analogous product is 

 obtained from other plants, and more especially (as has already been noticed) 

 from the Ferula tingitana, which is probably the origin of the Ammoniacum 

 of Dioscorides and Pliny, which they say was obtained from a plant growing 

 in Africa, in the vicinity of the temple of Jupiter Ammon, whence its name, 

 and not, as supposed by Mr. Don, from a corruption of Armeniacum. The 

 various opinions as regards the origin of this gum are deserving of a brief 

 notice. Lemery (Diet. 37) speaks of it as coming from Lybia, and calls the 

 plant producing it Femda ammonifera. Chardin (Voyages, iii. 299) says 

 that the plant affording it is very common in Persia, where it is called Ous- 

 chio c. Peyrilhe, in his translation of the " Materia Medica" of Linnaeus, at- 

 tributes it to a species of Pastinaca. Olivier, who visited Persia, but did not 

 reach the part of the country in which the plant grows, was of opinion, from 

 the information he obtained, that it was a species of Ferula, which he named 

 persica, but which, Willdenow asserts, produces sagapenum. This latter 

 writer raised a plant from seed picked from a fragment of the gum, and found 

 it to be a species of Heracleum, and called it gummiferum ; but admits that 

 he could obtain no gum-resin from it ; and later botanists consider that this 

 plant is identical with H. pyrenaicum, a native of the mountains of southern 



