Let us learn about Rutales; Family—Rutaceae. After reading this article you will learn about: 1. Introduction to Rutales 2. Explanation of Family—Rutaceae 3. Economic Importance.
Contents
Introduction to Rutales:
According to Hutchinson this is the forty seventh order of the phylum Angiospermae, subphylum Dicotyledones and division Lignosae. This order comprises of four families, i.e., Rutaceae, Simaroubaceae, Burseraceae and Averrhoaceae, of which the Rutaceae has been described in the present article in detail.
Bentham and Hooker placed the family Rutaceae along with other ten families including Lineae and Meliaceae in their seventh order-the Geramales of class Dicotyledones, division Polypetalae and series Disciflorae.
Engler and Prantl have also placed the Rutaceae along with nineteen other families including Linaceae and Meliaceae in the twenty third order-the Geraniales of class Dicotyledoneae and Subclass Archichlamydeae.
Hypogynous to slightly perigynous; bisexual or unisexual; apocarpous to syncarpous with axile, basal or apical placentation; ovules mostly few; stamens definite in number, free; petals contorted to valvate; disc mostly conspicuous; leaves often gland-dotted; endosperm present.
Explanation of Family—Rutaceae:
There are about 140 genera and 1300 species in this family.
Distribution:
They are widely distributed in warm temperate regions. They are also found in tropical regions. In our country the family is represented by several important genera such as, Citrus, Aegle, Feronia, Murraya, Ruta, etc.
Habit:
Usually the plants are trees or shrubs. Herbs are rarely found. Some of the shrubs are climbing and xerophytic. Aegle marmelos (Bel) and Feronia elephantum (Kaith) are large sized trees Murraya exotica is an ornamental shrub with scented white flowers. Sometimes the shrub becomes tree-like in habit.
Species of Citrus are small trees. They are grown in the gardens for their fruits rich in vitamins. Ruta graveolens is a strong-smelling herb which is a common garden shrub. The plant of Paraminya grifithii is a woody climber. This possesses strong curved spines.
It is believed that Citrus aurantium (Narangi) probably originated in Northern India and Assam. It has been cultivated since 1500 B.C.
Root:
Tap and branched.
Stem:
Usually erect, sometimes climbing branched, woody or rarely herbaceous, cylindrical, solid, green when young, grey when becomes old.
Leaves:
The leaves may be either simple or compound. They are usually alternate and rarely opposite. They are exstipulate. The leaves are dotted with glands. These glands contain volatile oils which give typical smell to the leaves. In most of the Citrus species the leaves possess winged petioles.
According to many authors the leaves with winged petioles are regarded as unifoliate palmate type of compound leaves. In early stages actually the leaf possesses three leaflets but on its maturity two of them fall off. In certain Australian genera such as Citrus, Feronia, etc., the leaves are reduced to spines. Such plants are extreme xerophytes.
Inflorescence:
The inflorescence consists of several variations in different species. Generally it is cymose, but sometimes it is racemose. In some cases the flowers are solitary axillary. In Murraya exotica the flowers are arranged in either axillary or terminal corymbs. In Citrus sp., the flowers are either solitary axillary or arranged in racemes.
Flower:
The flowers are pedicellate, complete, hermaphrodite, regular or occasionally slightly zygomorphic, white or yellow, hypogynous. A disc is present beneath the ovary. Usually pentamerous and rarely tetramerous, or trimerous. Sometimes the flowers are unisexual, e.g., Evodia, Zanthoxylum, etc.
Calyx:
There are usually five sepals. Sometimes only four sepals are found. Usually polysepalous but in the genera with zygomorphic flowers the calyx becomes either tubular or united. The aestivation is either imbricate or quincuncial.
Corolla:
There are usually five petals. Sometimes only four petals are present. The corolla is polypetalous. However, in an Australian species Correa speciosa, the petals become united attaining campanulate shape. The petals are coloured-white, yellow or red. The petals are inferior. The aestivation is imbricate.
Androecium:
Usually ten or eight stamens are present in obdiplostemonous condition. Sometimes the number of stamens decreases or increases to indefinite. In Citrus sp., and Aegle marmelos the stamens are indefinite. In such cases they are arranged in irregular bundles, i.e., polyadelphous condition. In Murraya exotica there are ten stamens arranged in two whorls of five each.
One whorl of stamens is alternating and the other antipetalous. The filaments are free. The anthers are bilobed, basifixed and introrse.
Gynoecium:
The gynoecium consists of 3, 4, or five carpels. Rarely it consists of a fewer number of carpels or indefinite carpels. The carpels are fused together, i.e., syncarpous. In most of cases the placentaion is axile. The ovary is tri to multilocular. Each locule contains one or more anatropous ovules. In Feronia, however, the placentation is parietal. In this a large number of ovules are arranged in several rows on the parietal placentas.
Fruit:
The fruits are of various kinds in different genera. They may be berry, drupe or capsule. In Murraya exotica the fruit is berry. The Citrus fruits are known as hespiridium (a berry). In Acronychia, the fruit may be capsule or drupe.
Seeds:
The seeds are endospermic or non-endospermic. Each seed contains a large straight very often curved embryo.
Pollination:
Usually entomophily, i.e., by means of the agency of insects. The nectar secreting disc found beneath the ovary is main source of attraction for the insects. The coloured and scented flowers also attract the insects.
1. Citrus aurantium:
Habit:
A small tree.
Root:
Tap and branched.
Stem:
Erect, woody branched, cylindrical, glabrous, and solid.
Leaf:
Cauline alternate, petiolate (petiole winged and flattened), stipulate, conacious, persistent, more or less serrate, acute or obtuse, glabrous, unicostate reticulate venation.
Inflorescence:
Cymose, solitary axillary or in small cymes.
Flower:
Pedicellate, bracteate, hermaphrodite, white or pinkish, scented, actinomorphic, complete, hypogynous.
Calyx:
Five sepals, gamosepalous, inferior, quincuncial aestivation.
Corolla:
Five petals, polypetalous, white, scented, inferior, imbricate aestivation, linear oblong.
Androecium:
Indefinite, stamens (15 – 60), inserted around, a large cupular or annular disc, polyadelphous, filaments variously connate, compressed at the base, anthers oblong, basifixed, introrse.
Gynoecium:
Polycarpellary, syncarpous, ovary superior, multilocular, nectar secreting disc present below ovary, axile, placentation, style stout, deciduous, stigma capitate.
Fruit:
Berry (hesperidium).
2. Murraya exotica; Verna-Kamini:
Habit:
Evergreen large shrub.
Root:
Tap, branched.
Stem:
Erect, branched, cylindrical, woody, green, solid.
Leaf:
Compound, pinnate, exstipulate, alternate, leaflets 3 – 7, oval, entire, smooth, coriaceous, alternate, petioled, unicostate reticulate venation, notched at the tip, dark green, shining above, and oblique at the base.
Inflorescence:
Cymose, short terminal and axillary corymbocymes.
Flower:
Pedicellate; ebracteate, pentamerous, hermaphrodite, complete, hypogynous, white, very fragrant, 1/2″ diameter.
Calyx:
Five sepals, five-fid or five partite, gamosepalous, minute, acute, inferior, quincuncial aestivation.
Corolla:
Five petals, polypetalous, white, fragrant, oblong lanceolate, spreading above, inferior, imbricate aestivation.
Androecium:
Ten stamens, inserted round an elongated disc, alternate filaments shorter, obdiplostemonous, anthers bi-celled, introrse, polyandrous.
Gynoecium:
Two or three carpels, syncarpous, ovary, superior, two or three locular, axile placentation, two ovules in each chamber, style filiform, disk present below ovary.
Fruit:
Ovoid berry, orange red when ripe.
3. Aegle marmelos Corr:
Verna. Bel; Eng. Bael, Bengal quince
Habit:
Large spinous tree.
Root:
Tap and branched.
Stem:
Erect, aerial, branched woody, cylinderical, solid, strong thorns present.
Leaf:
Palmately compound, trifoliate, exstipulate, petiolate, alternate, gland dotted, each leaflet ovate-lanceolate, acute, entire, glabrous, net-veined, unicostate reticulate, lateral sessile, terminal stalked, gland dotted.
Inflorescence:
Cymose, axillary panicles.
Flower:
Pedicellate, bracteate, hermaphrodite, actinomorphic, complete, hypogynous, yellowish white, disc present beneath ovary, pentamerous, sweet scented, cyclic.
Calyx:
5 sepals, polysepalous, valvate or imbricate, pubescent, deciduous.
Corolla:
5 petals, polypetalous, imbricate yellowish white.
Androecium:
Indefinite stamens, polyadelphous, polyandrous, filaments short, fascicled, basifixed, anther dithecous, introrse, elongate.
Gynoecium:
10, indefinite carpels, syncarpous, axile placentation, ovary superior, multilocular, each locule contains one or more ovules, style short and stout stigma capitate, sticky.
Fruit:
Berry, large, globose oblong or pyriform, rind woody, grey or yellow, pulp orange- coloured, sweet.
Economic value:
The ripe fruits are edible. The unripe fruits are used as an astringent, stomachic and also in the treatment of diarrhoea. The mucilaginous substance, secreted round the seeds, is used as a cement and is also employed as a varnish.
Economic Importance of Family – Rutaceae:
The family is fairly important from economic viewpoint as it consists of many fruit yielding and medicinal plants.
Some important plants are enlisted below:
1. Citrus aurantifolia; Syn. Limonia aurantifolia; Limonia acidisima; Citrus lima; C. medica var. acida; (Eng.-Lime; Verna.-Kaghzi-nimbu). A shrub or small tree, cultivated nearly all over the country. The oil distilled from the peel is mainly used in confectionery, pharmaceuticals and toilet preparations. The fruits are used for making jam, jellies, pickles and alcoholic drinks. It is a good source of vitamin C.
2. Citrus aurantium; (Eng.-Sour orange; Verna.-Khatta)-Not grown commercially anywhere in India but found scattered along with other Citrus. The fruits are edible. The leaves are the source of an essential oil, which is used in the preparation of cosmetics, perfumes and confectionery. Rich in vitamin C.
3. Citrus limettioides; C. medica var. limetta; (Eng.-sweet lime; Verna.-Mitha-nimbu)- They are mainly cultivated in Northern India and Madhya Pradesh for their edible frutis. They are also used as root stocks for sweet oranges. An essential oil is extracted from the leaves by means of distillation.
This oil is known as ‘Petitgrain oil’ which is used in perfumery, confectionery and cosmetics for flavouring purposes. Rich in vitamin C.
4. Citrus limon; Syn. C. medica var. limonum, C. limonum. (Eng.-Lemon, Verna- Baranimbu)-They are grown commonly in the Punjab and Uttar Pradesh by their popular name ‘galgal’. In Maharashtra and Deccan the fruits are known as ‘Pat nimbu’. The fruits are employed in the preparation of pickles and lemon squash. Good source of vitamin C.
5. Citrus maxima; (Eng.-Shadlock, Verna.-Chakotra)-Grown in Tamil Nadu, Karnataka, the Punjab and Uttar Pradesh. The fruits are edible. This is a good source of vitamin C.
6. Citrus medica; (Eng.-Citron, Verna.-Bara nimbu)-They are grown on the Khasia hills of Assam and sub-mountainous Himalayan ranges in Garhwal, Kumaon in the Uttar Pradesh. They are also found in the Punjab and South India. The fruits are edible and rich in vitamin C.
7. Citrus paradise; Syn. C. racemosa-, (Eng.-Grape fruit)-They are commonly grown in the Punjab, Uttar Pradesh, Madhya Pradesh and Bengal. The fruits are edible and rich in Vitamin C.
8. Citrus reticulate; Syn. C. nobilis (Eng.-Mandarin; Verna-Santara)-They are grown in Khasia and Darjeeling hills. They are also cultivated in the Punjab, Uttar Pradesh, Madhya Pradesh, Maharashtra and South India. The fruits are edible and rich in vitamin C.
The essential oil is extracted by means of distillation which is used in the manufacture of confectionery, perfumery and cosmetics, toilet products and pharmaceutical preparations.
9. Citrus sinensis; (Eng.-Sweet orange; Verna- Musambi)-They are grown for their edible fruits in South India, Maharashtra, the Punjab, Uttar Pradesh, Rajasthan and Tamil Nadu. Orange oil is extracted from the fruit peel.
10. Clausena dentata; A small tree found in the Western Ghats and Assam. The fruits are edible.
11. Aegle marmelos; (Verna-Bel) – A tall tree. The fruits are edible when ripe. The unripe fruits are used as an astringent, stomachic and in the treatment of diarrhoea. The medicines of stomach troubles are prepared from the pulp of ripe fruits. The mucilaginous substance secreted around the seeds is used as a cement and is used as a varnish.
The pulp of the fruit is a good laxative. The pulp is often used to strengthen mortar. The seeds yield a dye. The leaves are used as fodder. The leaves are employed in the worship of Lord Shiva by Hindu ladies.
12. Feronia limonia; Syn. F. elephantum’, (Eng.-Elephant apple; Verna-Kaith) – A tree found all over India. The fruits are with hard rind, large, globose and edible. The pulp of the fruits is eaten in many ways. It is also used in the treatment of diarrhoea and dysentery. The leaves are used as fodder. A gum is obtained from the trunk and branches of the tree.
13. Fortunella japonica; Syn. Citrus japonica; (Eng.-Kumquat)-This is a shrub or a small tree. It is native of East Asia, but now grown mainly in Northern India. The fruits are edible. The shrub is ornamental.
14. Fortunella margarita; Syn., Citrus margarita- This is an ornamental shrub possessing edible fruits.
15. Acronychia pedunculata; A small tree. The leaves yield an essential oil. The tender leaves are used as condiment. It is found in Dehradun, West Bengal and Khasia hills of Assam.
16. Glycosmis pentaphylla; (Verna-Ban-nimbu)-The ripe fruits are edible. The branches are used as tooth-brushes.
17. Luvunga scandens; (Verna-Long-phul)-A large, thorny climbing ornamental shrub, with beautiful scented white flowers. They are found in Bengal and Assam. The fruits yield an essential oil which is used in perfumery and pharmaceuticals.
18. Murray a paniculata; Syn. Murraya exotica; (Verna-Kainini)-This is an ornamental shrub possessing white scented flowers. The fruits are edible.
19. Murraya koenigii; (Verna-Mitha neem)- A large shrub or small tree. Cultivated in both Northern and South India. The leaves are used for flavouring curries.
20. Ruta graveolens; (Verna.-Sadab)-A herb, cultivated throughout country. The leaves are used as condiment and for flavouring curries. It also possesses medicinal properties.
21. Toddalia asiatica; (Verna.-Kanj)-A shrub. It is found in sub-tropical Himalayas. The root yields a yellow dye. The leaves and fruits are edible. The pickle is prepared from the fruits.
22. Zanthoxylum alatum; (Verna.-Tejbal)- A small tree found in sub-tropical Himalayas. The seeds are used as tonic. The walking sticks are made from its wood. The branches are used as tooth brushes.
23. Fagara budrunga; Syn. Zanthoxylum rhesta; (Verna-Badrang)-A large tree. It is found in Western Ghats and West Bengal. An aromatic oil is extracted from its seeds. The fruits are used as spice. The wood is used in making shuttles.
24. Fagara oxyphylla; (Verna-Timar)-A shrub found in the hills of Kumaon and Assam. The tender shoots are used as vegetable.
Systematic Relationships:
Hutchinson has placed the family Rutaceae along with three other families in the order-Rutales. Earlier this view was put forth by Rendle and accepted by Wettstein in principle.