Rutaceae – Citrus aurantium

Rutaceae (Citrus Family)

The members of the family are worldwide in distribution in warm temperate and tropical regions of the world. The family comprises of 140 genera 1300 species. In Pakistan, the family is represented by Citrus aurantium (Orange), Murraya exotica (kamini), Ruta graveolens (a strong-smelling herb), etc.

Distinguish Features:

Shrubs or small tree, simple alternate leaves, dotted with glands, flower hermaphrodite, actinomorphic, hypogynous, pentamerous, stamen 10 in number, ovary is multi-chambered.

The representative species are:

Citrus aurantium (Orange)

Citrus aurantium (Orange):

Habit:

It is a small tree grown in gardens for their fruit rich in vitamin C. The leaves are the source of an essential oil used in confectionery, cosmetics and perfumery.

Root:

Tap root, branched, perennial.

Stem:

Erect, branched, woody, spiny.

Leaf:

Ever green, cauline and ramal, alternate, stipulate, petiolate, winged, flattened, reticulate, unicostate, leaf margins more or less serrate, gland dotted, glaucous.

Inflorescence:

Cymose – Solitary axillary or in small raceme.

Flower:

Ebracteate, pedicellate, complete, hermaphrodite, actinomorphic, bisexual, pentamerous, hypogynous, white or pinkish.

Calyx:

5 sepals, gamosepalous, sepal’s gland dotted, green, inferior.

Corolla:

5 petals, polypetalous, petals lanceolate, white in color and scented, imbricate, inferior, gland dotted.

Androecium:

Stamens indefinite inserted round a large cup-like or circular disc, polyandelphous, filaments compressed at the base, anthers oblong and basifixed, inferior.

Gynoecium:

Polycarpellary, syncarpous, ovary superior, multilocular, placentation: axile, stigmas capitate, a nector secreting disc is present below ovary.

Floral Formula: K (5) C5 A (∞) G (5)

Economic Importance of the Family:

Fruits:

The most important genus of the family, the citrus furnishes the various types of “citrus fruit” including oranges, limes, lemons and grape-fruits. So intensively are they grown that the family takes third place in fruit production. Their good peeling and shipping qualities combined with their fine flavor and wholesomeness, ensures their continued prominence in the market. Besides citrus fruits, the genus Feronia yields elephant-apple (Kaith) and Aegle Yields Bael fruits. Zanthoxylum yields Japanese pepper.

Medicine:

Most of the plants are great medicinal value on account of high vitamin contents and mineral salts. In recent years, they have been much exploited for their contents of vitamin C, the anti-scorbutic vitamin. Aegel (Bael) fruit is used as medicine because of the presence of tannic acid, leaves of Murraya koenigii (Mithaneem) are used in flavouring curries, while the dried leaves of Benning-hausenia alblflora are believed to be effective against fleas and moths. Twigs of Zanthoxylum alatum are used as tooth brushes because of their medicinal properties of gums. Citron oil and oil of lemon is extracted from the gland-dotted leaves and peelings of fruits and is used in the presence of mosquito-oil. Citrus limon is frequently grown as a hedge.

Ornamental Plant:

Plants like Murraya, Ruta and Limonia are cultivated in the gardens for their fragrant flowers or foliage.

Source of Perfumes:

The large white fragrant flowers, and the young fruits of some species are used in the perfume manufacturing. From Pilocarpous Jaborandi, oil of Jaborandi is obtained.

Some Important Genera of Family:

Citrus aurantium (orange)

Murraya exotica (kamini)

Ruta graveolens

Citrus acida (khatta)

Citrus medica (lemon)