Rutaceae: Characters, Distribution and Types

In this article we will discuss about:- 1. Characters of Rutaceae 2. Distribution of Rutaceae 3. Economic Importance 4. Affinities 5. Important Types.

Characters of Rutaceae:

Leaves gland dotted, simple or compound; flower hermaphrodite, hypogynous, actinomorphic with a disc below the ovary; corolla polypetalous; stamens ten, obdiplostemonous; carpels 5 or many, ovary superior, multilocular; fruit capsule or berry; aromatic odour is present.

A. Vegetative characters:

Habit:

The plant are generally shrubs (Murray a, Limonia, Zanthoxylum), trees (Aegle, Citrus, Feronia), rarely herbs (Ruta graveolens) with strong fragrance Paramignya is a shrub but climbs by means of axillary thorns.

Root:

Tap root, branched often infected with fungus.

Stem:

Woody (Citrus, Feronia), erect, cylindrical, branched, solid often thorny (Citrus), gland dotted.

Leaves:

Alternate (Citrus, Murraya) or opposite (Evodia), petiolate, petiole may be winged (Citrus aurantium), simple or compound-pinnate (Murraya), palmate (Aegle and Citrus) smooth gland dotted, glands with essential oils, exstipulate, margin entire or serrate, unicostate reticulate venation. In Citrus petiole is winged.

B. Floral characters:

Inflorescence:

Usually cyme or axillary or terminal corymb (Murraya paniculata) some times racemose or solitary.

Flower:

Pedicellate, ebracteate, hermaphrodite, or unisexual (Zanthoxylum, Evodia, Feronia), actinomorphic rarely zygomorphic (Dictamnus and Correa), hypogynous, complete, pentamerous or tetramerous (Acronychia and lateral flowers of Ruta).

Calyx:

Sepals 5 or 4, free or fused; in zygomorphic flower it becomes gamosepalous and tubular; imbricate; sometimes deciduous.

Corolla:

Petals 5 or 4, polypetalous rarely gamopetalous (Correa speciosa) or absent (Zanthoxylum), variously coloured, imbricate.

Androecium:

In majority of cases the stamens are obdiplostemonous and 10 in number; in Citrus numerous stamens with polyadelphous condition; in Zanthoxylum 3 stamens and in Skimmia 5 stamens; anthers introrse, dithecous, basifixed or versatile.

Gynoecium:

Pentacarpellary and only slightly united at the base or the sides forming a deeply lobed ovary with fused styles originating from the centre. In Citrus and Toddalia the carpels are fully united. In Feronia the carpel is only one celled with many parietal placentae. In other genera the placentation is of the axile type. Topically the ovary is superior with a prominent nectariferous disc below it. Ovule anatropous.

Fruit:

In Flindersioideae there is septicidal or loculicidal capsule; in Toddalioideae a drupaceous fruit; hesperidium in Citrus and berry in Murraya.

Seed:

Endospermic or exalbuminous.

Pollination:

Entomophilous; insects are attracted by the coloured petals, the nectar secreted by the disc is easily available. The flowers are protandrous. Thus in Ruta the stamens arise
successively to the centre of the flower and after shedding the pollen grains wither away and fall back again.

The stigma now matures and if no insect visitor has come then the stamens rise again and the pollen grains that still remain are once again shed over the stigma. Thus self pollination is effected.

Floral formula:

Distribution of Rutaceae:

The family is commonly is called orange family. The family comprises 150 genera and 1300 species out of which India contributes 71 species. The members of the family are distributed in tropical and temperate regions and they are predominant in South Africa and Australia.

Economic Importance of Rutaceae:

1. Fruits:

The genus Citrus provides a number of fruits:

(a) C. aurantifolia (H-Kaghzi nimbu) has citric acid in its fruits and used in bilous vomiting. The fruit wall has essential oils.

(b) C. aurantium var. bergamia (H-Nimbu). The ripe fruit is digestive and a tonic, fruit wall gives oil of bergamot.

(c) C. aurantium var. bigardia. (H-Khatta). Rich in pro-vitamins A and vitamin B. Oil present in fruit wall.

(d) C. maxima (H-Chakotra) produces edible fruits.

(e) C. sinensis (H-Musumbi). The fruit is widely used during illness; it purifies blood, reduces thirst and improves appetite.

(f) C. reticulata (H-Santara or Narangi). The ripe fruit is highly nutritive and rich in assimilable calcium, the fruit wall also produces citrus oil.

(g) C. limettioides (H-Mitha Nimbu) is useful in fever and jaundice; oil also obtained from the wall.

(h) C. limon (H-Pahari Nimbu). The juice of ripe fruits is useful in rheumatism and dysentery.

(i) Aegle marmelos (H-Bel). This is normally edible. The fruit is particularly useful in stomach disorders. The plant is considered holy and its leaves used in worshipping the God Shiva.

(j) Feronia limonia (H-Kaith bel). The fruits edible; leaf and bark used medicinally.

2. Medicinal:

Citrus is not only edible but produces vitamins particularly vitamin C (ascorbic acid). Barosma betulina produces buchu from its leaves which is useful in urinary diseases.

Pilocarpus microphyllus:

The active principle is pilocarpine which causes contraction of the pupil – it is just opposite to atropine. Jaborandi is prepared from the leaflets of this plant; this is useful in kidney diseases.

Murraya koenigii. (H-Katnim) has several medicinal properties. The green leaf is eaten raw in dysentery while bark and roots are useful in bites of poisonous animals when applied externally. The leaves are also used in curry powder particularly by S. Indians.

3. Ornamental and miscellaneous:

Plants like Ruta, Luvunga scandens, Ptelea, Calodendrum, Limonia, Murraya are cultivated in gardens for their fragrant flowers.

Zanthoxylum piperitum gives Japan pepper. Ruta graveolous gives French oil of Rue; Galipea officinalis yields cusparia bark.

Primitive characters:

1. Plants are mostly trees (Feronia, Aegle) and shrubs (Citrus).

2. Flowers hermaphrodite, hypogynous, actinomorphic and scented.

3. Corolla free.

4. Stamens many in some genera (Aegle, Skimmia).

5. Seeds endospermic.

Advanced characters:

1. Leaves compound in most genera.

2. Flowers unisexual in Feronia, Toddalia.

3. Flowers zygomorphic in Galipea, Dictamnus, Almeidea.

4. Flowers trimerous in Triphasia, Lunasia.

5. Calyx gamosepalous.

6. Corolla gamopetalous in Correa, Ticorea and Galipea.

7. Stamens number is reduced to 5 (Skimmia) from many (Citrus, Aegle).

8. Gynoecium syncarpous and reduction in the number of carpels to one (Empleurum).

9. Seeds non-endospermic.

Affinities of Rutaceae:

Engler and Prantl included the family in the Geraniales along with Zygophyllaceae. Euphorbiaceae and Burseraceae. Hallier attached particular phylogenetic significance to the Rutaceae and derived it from stocks ancestral to Berberidaceae; Rendle placed the family in a separate order between Geraniales and Sapindales. Wettstein included Rutaceae along with Meliaceae in the order as Terebinthales.

Engler gave the relationship to Rutaceae to allied families as:

Rutaceae is related to the Meliaceae, Sapindaceae and Anacardiaceae in habit, leaf structure, presence of disc around the ovary and obdiplostemonous condition of androecium. The family Rutaceae is also related to Euphorbiaceae on account of the presence of ventral raphe of the ovule in some genera.

According to Tillson and Bamford (1938) the disc in the members of sub-family Aurantioideae represents the vestigeal third whorl of stamens.

Common plants:

Citrus:

Cultivated for fruits.

Aegle:

Leaves are indispensable for the worship of Lord Shiva.

Murraya:

Leaves, roots and barks are used for flavouring curries.

Zanthoxylum:

Prickles are present all over its body.

Ruta:

Whole plant is aromatic.

Feronia – (Kaith bael):

Fruits are of the tennis ball size.

Division of the family and chief genera:

Engler has divided the family into five sub-families on the basis of fruit character:

1. Rutoideae:

Carpels usually 4-5, often only united by style, loculicidal dehiscence of fruit usually with the separation of endocarp.

This is again divided into five tribes such as Zanthoxyleae, Ruteae, Boronieae, Diosmeae and Cusparieae. Zanthoxylum, Ruta, Correa, Diosma, Cusparia.

2. Dictyolomatoideae:

Carpels with several ovules, united at the base; fruit with separating endocarp. Dictyoloma.

3. Spathelioideae:

Carpels three, syncarpous, each carpel with 2 pendulous ovules; fruit drupe and winged. Spathelia.

4. Toddalioideae:

Carpels 5-2 or 1, each with 2-1 ovules; fruit drupe or dry winged. Toddalia, Ptelea, Skimmia.

5. Aurantioideae:

Fruit berry often with periderm and with pulp derived from sappy emergences of carpel wall. Aegle, Citrus, Limonia, Feronia.

Important Types of Rutaceae:

1. Murraya paniculata (Syn. M. exotica) (Fig. 45.4):

Habit:

A cultivated perennial shrub.

Root:

Tap, much branched.

Stem:

Erect, woody, solid, cylindrical, branched, rough.

Leaves:

Cauline and ramal, alternate, petiolate, exstipulate, pinnately compound- imparipinnate, leaflets 5-7.

Inflorescence:

Terminal or axillary monochasial cyme.

Flower:

Pedicellate, bracteate, hermaphrodite, actinomorphic, complete, pentamerous, hypogynous, white coloured and highly fragrant.

Calyx:

Sepals 5, gamosepalous, oblong, green, valvate aestivation, inferior.

Corolla:

Petals 5, polypetalous, white, gland dotted, imbricate aestivation, inferior.

Androecium:

Stamens 10, in two whorls of 5 each, polyandrous, filaments of the outer whorl longer while those of inner whorl are shorter; anthers basifixed, dithecous, introrse.

Gynoecium:

Bicarpellary, syncarpous, ovary superior, bilocular, axile placentation. one ovule in each loculus; style slender; stigma bilobed, capitate, disc below the ovary.

Fruit:

Berry.

Floral formula:

2. Citrus aurantium (Fig. 45.5):

Habit:

A small tree.

Root:

Tap, branched.

Stem:

Erect, woody, solid, cylindrical, branched, glabrous.

Leaves:

Cauline, ramal, alternate, petiolate, petiole winged; stipulate, compound unifoliate palmate, coriaceous, apex obtuse, crenate margin, unicostate reticulate venation, gland dotted.

Inflorescence:

Axillary cyme.

Flower:

Pedicellate, bracteate, complete, hermaphrodite, actinomorphic, hypogynous, white, scented.

Calyx:

Sepals 5, gamosepalous, pentafid, greenish, inferior, quincuncial aestivation.

Corolla:

Petals 5, polypetalous, white, imbricate aestivation, inferior.

Androecium:

Stamens indefinite, polyadelphous, inserted round the cup-shaped disc, filament flat at the base, anthers yellow, basifixed, dithecous introrse.

Gynoecium:

Polycarpellary, syncarpous, ovary superior, seated on a cupular honey secreting disc; multilocular, axile placentation, one ovule in each loculus; style stout and short; deciduous; stigma capitate.

Fruit:

Hesperidium.

Floral formula: