810. 
CITRIC ACID. 
and numerous, and are produced, on long foot- 
stalks, at the ends of the branches.—The other 
species most commonly cultivated are those de- 
signated appeninus, albidus, grandiflorus, crispus, , 
helianthemum, alpestris, Italicus, algarvensis, laxus, 
proliferus, halimifolius, salvifolius, roseus, mari- 
folius, mutabilis, and surrejanus. 
CITRIC ACID. The peculiar acid of many 
acidulous fruits, particularly of the juice of limes, 
lemons, oranges, and currants. It is believed to 
be the active principle which renders these fruits 
so powerfully antiscorbutic; and it has some- 
times been recommended, in the room of lemon- 
juice, as a preventive of sea-scurvy. It has a 
cooling and grateful effect, as an ingredient in 
drinks; yet it probably acts with most benign 
effect, especially in counteracting the putrefac- 
tive tendency of animal food, when used in its 
natural state of combination with the sugar, mu- 
cilage, and extractive of fruits. It is obtained 
in a separate state by adding finely pulverized 
chalk to lemon-juice, so as to form insoluble 
citrate of lime,—by washing this citrate with 
water, and decomposingly digesting it in diluted 
sulphuric acid,—by infiltrating the liquid from 
the insoluble sulphate of lime,—and by evapo- 
rating the liquid to dryness, so as to drive off all 
the water, and leave the citric acid as a resi- 
duum. The acid crystallizes into large trans- 
‘parent rhomboidal prisms; it consists of four 
equivalents of carbon, four of oxygen, and two of 
hydrogen ; it keeps for any length of time unde- 
composed in dry jars or bottles, but is slowly and 
gradually decomposed when damp or in watery 
solution; and it is convertible into the highly 
poisonous oxalic acid, by the action of nitric acid. 
The principal salts formed by it are the citrates 
of potash, soda, ammonia, magnesia, lime, iron, 
baryta, and strontia; but—excepting the first, 
which is often extemporaneously made in solu- 
tion as an effervescing draught—they are of very 
small importance. 
CITRUL. See CucumBer. 
CITRUS. A very rich and important genus 
of tropical fruit-trees, containing the type of the 
order Aurantiacese. It is distinguished from the 
other genera of this order, by the multitudinous- 
ness and irregularly parcelled combination of its 
stamens, and by the looseness with which the 
leathery rind of its fruit is attached to the en- 
veloped bags of pulp. Fifteen species, besides 
varieties, all ranking as cultivated tropical fruit- 
trees, are enumerated by some botanists; but 
these are referred by other writers to four types 
or specific sources,—all the kinds except these 
four being regarded as either natural varieties or 
artificial hybrids. Full notices of the whole, or 
of the several groups and most important kinds, 
will be found in our articles AURANTIUM, ORANGE, 
Lemon, Crrron, Limr, Manparin, and SHADDOcK. 
CIVES. See Cuives. 
CLARKIA. A small genus of very beautiful, 
hardy, annual plants, of the order Onagrarie. 
CLARY. 
The elegant species, Clarkia elegans, was intro- 
duced from California in 1832. Its stem is erect, 
and between two and three feet high, and sends 
off numerous, erect, twiggy, rounded, glabrous, 
leafy branches ; its leaves are ovate, acute, gla- 
brous, and more or less distinctly toothed, and |! 
stand on short footstalks; and its flowers have 
four equal, spreading, somewhat rhomboidal, 
clawed, and deep rose-coloured petals, stand out 
horizontally, are quite sessile, and bloom from 
July till the end of autumn. A variety of this 
species has double flowers, of a palish rose colour. 
—The gaura-like species, Clarkia gauroides, was 
introduced from California in 1834. Its stem is | 
erect, filiform, pale green, stained with purple, 
clothed with pubescence, much branched, and 
about a foot high ; its leaves are alternate, 
stalked, ovate, acute, entire, an inch long, dark 
green and glabrous above, and paler and pubes- 
cent below; and its flowers are scattered in ter- 
minal racemes, begin to bloom in August, and 
have four purple petals, with very short claws, and 
rhomboidal, obtuse, concave, crenulately repand 
laminze, furnished just above the claw with two 
short auriculate lobes. — The pretty species, 
Clarkia pulchella, was introduced from the terri- 
tories of the Hudson Bay Company in 1826; and 
is already in so general favour, that it may be 
seen in every garden, from the tiniest to the 
most noble, in which the slightest taste or know- 
ledge of plants is displayed. It has a height of 
about 18 inches, is ramose and sheeted all over 
with very showy, segmented, rosaceously-purple 
flowers, and is, in all respects, one of the best. of 
our hardy flowering annuals. A permanent va- 
riety of it, Clarkia pulchella flore albo, has white- 
coloured flowers. 
CLARY,—botanically Salvia. Several species 
of hardy herbaceous plants, of the sage genus. 
The common species, Salvia sclarea, was intro- 
duced from Italy in 1562. Itis a biennial, of about 
four feet in height, with large leaves, and carry- 
ing light blue flowers from July till September ; 
and it is frequently cultivated, as an aromatic 
herb, in kitchen gardens. Its flowers are used 
for making wine; and its leaves are employed 
for various culinary purposes. It is sown in 
spring, and transplanted in summer at distances 
from plant to plant of between 6 and 12 inches, 
—The Horminum species, Salvia Horminum, was 
introduced from the south of Europe in 1596. It 
is an annual of 12 or 18 inches in height, and 
carries a purple-coloured flower in June and 
July; and is also occasionally cultivated as an. 
aromatic herb. Two varieties of it, the purple- 
topped and the red-topped, S. H. violacea and 
S. H. rubra, are cultivated both for economical 
purposes and for ornament.—The meadow spe- 
cies, Salvia pratensis, is a perennial-rooted and 
rare weed of the dry pastures of England. Its: 
stem is 3 or 4 feet high; its leaves are dark 
green; and its flowers are large, violet-coloured, — 
and handsome, and bloom from May till Novem- 
