SOLANACER. 627 
gative property of the juice is essentially due to the presence of 
peculiar glucosides. In the roots of other species this purgative 
principle is either absent or in but small quantity, and starch 
or sugar predominates, which renders them edible. The seeds 
of some species are also purgative. The Cuscutez are leafless 
parasites, which often do great damage in clover- and flax-fields 
&c. by destroying the plants from which they draw their nour- 
ishment. 
Convolvulus, Bindweed.—From the incised living root of C. Seammonia, 
a native of Asia Minor and Syria, the purgative gum-resin called Scammony 
is obtained. This Scammony as also Scammony Root, and Scammony Resin, 
are official in the British Pharmacopeeia. The best and greater part of the 
Scammony of English commerce is imported from Smyrna. The roots of 
many other species also possess in a certain degree purgative properties; as 
those of our native species, Convolvulus ( Calystegia) sepium, C. arvensis, and 
C. Soldanella. It is said that Convolvulus dissectus yields hydrocyanic acid 
when distilled with water. It is one of the plants used for flavouring Noyau. 
Ipomea.—Ipomea Purga(Exogonium Purga) isa native of Mexico, near 
Chicanquiaco. Its tubercular roots constitute the true Jalap of the Materia 
Medica, so well known as a purgative ; these properties are especially due 
to the glucoside convolvulin. Jalap is official in the British Pharmacopeeia. 
The roots of J. orizabensis are sometimes found intermixed with true 
jalap. This spurious jalap is known in Mexico as male jalap, and in Eng- 
lish commerce as woody jalap or jalap wood, and on the Continent as light 
or fusiform jalap. It possesses similar, although somewhat less powerful 
properties to those of true jalap ; these properties are due to the glucoside 
jalapin. The roots of I. Turpethum, Turpeth, were formerly much used asa 
purgative. The large roots of J. macrorhiza contain much farinaceous matter, 
and are eaten by the inhabitants of the States of Georg'a and Carolina.—J, 
pandurata is the Mechameck of the Indians of North America ; its roots 
are said to be purgative and somewhat diuretic. Tampico jalap, now fre- 
quently employed as a substitute for true jalap, is derived from Zpomea 
simulans. It appears to be nearly, if not quite, as powerful as the official 
kind.—Ipomea ( Pharbitis) Nil. ‘The seeds are official in the Pharmacopeia 
of India, under the name of Kaladana. They possess similar medicinal 
properties to our official jalap, but are not quite so active—IJpomea 
( Batatas) edulis. The tubercular root of this plant constitutes the Sweet- 
Potato, which is so largely used for food in many tropical countries. 
Rhodorrhiza.—From the species of this genus, natives of the Canary 
Islands, the volatile oil called Oil of Rhodium is commonly said to be ob- 
tained ; but at the present time the so-called oil of Rhodium of commerce is 
a mixture compounded according to the taste of the vendor and the pocket of 
the buyer. The powdered wood is also used for snuff, and for fumigation, 
Order 10. SotaNnacE&, the Solanum Order.—Character.— 
Herbs, or rarely shrubs, or trees, with a colourless juice. Leaves 
alternate, often in pairs. Inflorescence axillary, or frequently 
extra-axillary (fig. 354). Flowers isomerous (fig. 1015). Calyx 
(fig. 1015) with 5 or rarely 4 divisions, usually persistent, often 
growing during the ripening of the fruit (accrescent). Corolla 
(fig. 1015) regular or somewhat irregular, 5- or rarely 4-partite ; 
estivation valvate, induplicate, plaited, or imbricate. Stamens 
equal in number to the lobes of the corolla, with which they 
are alternate (figs. 1015 and 1019) ; anthers 2-celled, sometimes 
connate above, with longitudinal or porous dehiscence (figs. 
S82 
