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The below mentioned article provides an overview on Family–Apocynaceae. After reading this article you will learn about: 1. Explanation on Family Apocynaceae 2. Economic Importance.
Explanation on Family Apocynaceae:
There are about 300 genera and 1300 species in this family.
Distribution:
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The members of this family are found throughout the world, but they are more commonly met with in the tropical regions.
Habit:
There is a great variation in the habit of the plants of this family. They may be herbs, erect or twining shrubs or trees. Vinca rosea (Verna-Sadabahar) is a perennial herb; Vallaris solanacea (Verna-Ramsar) is a large twining shrub; Nerium indicum (N. odorum) is a large shrub with beautiful red or white flowers; Thevetia peruviana or Thevetia nerifolia (Verna-Pili kaner) is a large shrub or a small tree; Plumeria acutifolia is a small sized tree and Alstonia scholaris is a medium sized tree. In some genera, the stem becomes tuber like, e.g., Adenium. The species of Landolphia and Clitandra are climbing shrubs.
The latex is present in most of the genera.
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Root:
Tap and branched.
Stem:
Usually erect, branched, solid, glabrous rarely tuber-like and thick.
Leaves:
The leaves are simple, petiolate, usually opposite decussate. In rare cases the leaves are alternate or even whorled (e.g., in Nerium odorum, Alstonia, etc.) Usually the leaves are exstipulate and very rarely they may be stipulate.
Inflorescence:
Usually the inflorescence is of cymose type. It is very rarely solitary as in Vinca. In Carissa, the flowers are found to be arranged in corymbose cymes. In Plumeria, the flowers are arranged in terminal cymes. In Alstonia, the flowers are found to be arranged in umbellate branched panicled cymes. In Rauvolfia, the flowers are arranged in umbellate or corymbose cymes.
Flowers:
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The flowers are pedicellate, bracteate, bracteolate, hermaphrodite, actinomorphic, regular, sometimes slightly, zygomorphic, complete, hypogynous and pentamerous. In rare cases the flowers are tetramerous with reduction to two in the pistil.
Calyx:
Usually it consists of five sepals, gamosepalous. The calyx is generally divided almost to the base. The aestivation is quincuncial.
Corolla:
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Usually the corolla consists of five petals, gamopetalous. It is generally salver or funnel shaped. The corolla tube usually possesses hairy appendage or scales. The aestivation is contorted.
Androecium:
It consists of five stamens alternating with the petals. The stamens are situated on the tube or the throat of the corolla (i.e., epipetalous). The filaments are short; anthers introrse, polyandrous or connate and often adhere to the stigma. The antherlobes are sometimes empty at their base and prolonged into spines.
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Gynoecium:
It consists of two carpels. The carpels may be free (apocarpous) or connate (syncarpous); superior, sometimes partly inferior as in Plumeria. The style is simple and the stigma is thick and often bilobed. Rarely the number of carpels exceeds, i.e., 3 to 5. Usually a nectar secreting disc is situated beneath the gynoecium.
In syncarpous gynoecium, the ovary may be unilocular with parietal placentation or it may be bilocular with axile placentation. In the case of separate ovaries the placentation is marginal. The ovary is superior or half-inferior. Numerous ovules are found to be situated on parietal placentas or in two chambered ovaries on marginal walls.
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Fruit:
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In the case of free ovaries, the fruit is a pair of follicles. Sometimes the fruits of separate ovaries are fleshy and indehiscent, or may be one seeded, e.g., Cameraria. In the case of syncarpous ovary, usually the fruit is indehiscent, fleshy and berry-like, e.g., in Landolphia. In Cerbera, it may be a drupe.
This fruit is coconut like and distributed by means of water currents. In certain genera, possessing syncarpous ovaries a two-valved capsule is found, e.g., in Aspidosperma and Allamanda.
Seed:
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In dry fruits the seeds are generally winged, e.g., in Plumeria. Sometimes the seed bears a tuft of hairs at the base, e.g., in Kickxia, and sometimes at both ends, e.g., In Strophanthus. The embryo is straight, with or without endosperm.
Pollination:
Generally it takes place through the agency of insects.
Description of important plants in semi-technical language:
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1. Vinca rosea; Verna.-Sadabahar:
Habit:
A perennial herb.
Stem:
Erect, cylindrical, branched, solid, reddish green, glabrous.
Leaf:
Cauline, simple, opposite, decussate, petiolate, exstipulate, obovate, entire, glabrous, mucronate apex, unicostate reticulate venation.
Inflorescence:
Cymose, flowers arranged in axillary pairs.
Flower:
Pedicellate, bracteate, hermaphrodite, actinomorphic, complete, pink, hypogynous.
Calyx:
5, polysepalous, glandular, green, inferior, quincuncial aestivation.
Corolla:
5, gamopetalous forming corolla tube, throat of corolla tube hairy forming a corona, contorted aestivation.
Androecium:
5, free, epipetalous, alternate to petals, almost sessile, anthers dorsifixed, connivent round the stigma, yellowish.
Gynoecium:
2 carpels (bicarpellary), syncarpous, carpels united above in the region of style and stigma, ovaries free (apocarpous below), with single style and stigma, ovaries superior nectar secreting disc present beneath ovaries, unilocular, marginal placentation, glands present alternating with the carpels, style filiform, stigma thickened, dumb-bell shaped.
Fruit:
A pair of elongated follicles.
2. Plumeria acutifolia; Verna.-Goburchampa:
Habit:
A large shrub or small tree.
Stem:
Erect, solid, branched, woody, latex present, glabrous, green, and cylindrical.
Leaf:
Simple, whorled, petiolate, margin smooth, apex acute, unicostate reticulate venation large.
Inflorescence:
Cymose.
Flowers:
Pedicellate, bracteate, hermaphrodite, actinomorphic, complete, hypogynous.
Calyx:
5, polysepalous, imbricate aestivation.
Corolla:
5, gamopetalous forming a corolla tube, twisted aestivation.
Androecium:
5, free, epipetalous, included in the corolla tube, introrse, two-celled, basifixed.
Economic value:
Grown as an ornamental. The red pulp around seed is used as a dye. Wood is refrigerant. Milky juice is used for diseases of eye. Root is acrid, bitter, used as local anodyne and chewed for relief of toothache. (Fig. 19.3)
Gynoecium:
2 (bicarpellary), syncarpous, ovary superior or partly inferior, bilocular, axile placentation, style one, stigma simple.
Economic value:
A beautiful shrub; grown as a hedge plant. Plant is poisonous. Root is powerful resolvent and attenuant; used externally. Oil prepared from root bark is used in skin diseases and leprosy.
3. Tabernaemontana divaricata (Linn); R. Br.; Verna. Chandni; Eng. Crape jasmine:
Habit:
A large shrub.
Stem:
Erect, solid, branched, woody, latex present, glabrous, green, and cylindrical.
Leaf:
Cauline and ramal, simple, opposite, margin smooth, apex acute, unicostate reticulate venation.
Inflorescence:
Cymose, terminal cyme.
Flower:
Pedicellate, bracteate, bracteolate, hermaphrodite, actinomorphic, complete, hypogynous, pentamerous, cyclic, white.
Calyx:
5, gamosepalous, valvate or imbricate aestivation.
Corolla:
5, gamopetalous, forming a corolla tube, twisted aestivation.
Androecium:
5, free, epipetalous, included in the corolla tube, introrse, two-celled, basifixed.
Gynoecium:
2(bicarpellary), syncarpous, ovary superior or partly inferior, bilocular, axile placentation, style one, stigma simple, bifid, several ovules in each locule.
4. Nerium indicum Mill.; Verna. Kaner; Eng. Oleander:
Habit:
A large shrub or small tree.
Stem:
Erect, aerial, solid, woody, cylindrical, glabrous, branched, nodes swollen, milky latex present.
Leaf:
Cauline and ramal, simple, whorled with three leaves in each whorl, sub-sessile, exstipulate, linear-lanceolate; unicostate reticulate venation, latex present.
Inflorescence:
Cymose, terminal dichasial cyme.
Flower:
Pedicellate, braceate, bracteolate, hermaphrodite, actinomorphic, complete, yellow, hypogynous, pentamerous, cyclic, pink.
Calyx:
5, polysepalous, quincuncial aestivation, purple red.
Corolla:
5, gamopetalous, campanulate, corolla tube expanding above, throat of corolla tube hairy forming a corona, yellow, contorted aestivation, red or white.
Androecium:
5, epipetalous included in the corolla tube, alternating with the petals, polyardrous, filaments short, anthers connivent round the stigmatic head, basifixed, long hair appendages present on their apices, dithecous, introrse, protruded feathery connective present.
Gynoecium:
Bicarpellay, syncarpous, ovary superior, bilocular, many ovules in each loculus, axile placetation, a nectar secreting disc present beneath the ovary, style long filiform, stigma thickened and dumb-bell shaped.
5. Thevetia peruviana Pers. Syn. T. neriifolia Juss.: Verna. Pili kaner; Eng. Yellow oleander:
Habit:
Large shrub or small tree.
Root:
Tap, branched.
Stem:
Erect, aerial, solid, woody (old) or herbaceous (young), cylindrical, smooth, milky latex present.
Leaf:
Cauline and ramal, exstipulate, sub-sessile, spiral, linear-lanceolate, entire, acute, glabrous, unicostate reticulate, latex present.
Inflorescence:
Cymose, axillary dichasial cyme.
Flower:
Bracteate, bracteolate, pedicellate, complete, actinomorphic, regular, hermaphrodite, pentamerous, hypogynous, cyclic.
Calyx:
5 sepals, polysepalous, quincuncial aestivation, persistent, green.
Corolla:
5 petals gamopetalous, twisted aestivation, bell-shaped (infundibuliform), yellow fringed coronary outgrowths present.
Androecium:
5 stamens, polyandrous, epipetalous, stamens inserted at the throat of corolla, filament short anther sagittate, dithecous, basifixed and introrse.
Economic value:
The bark is bitter, cathartic, febrifuge and useful in different kinds of intermittent fevers. Milky juicy and seeds are poisonous. (Fig. 19.5)
Gynoecium:
2 capels (bicarpellary), syncarpous, ovary superior, bilocular, two ovules in each locule, axile placentation, style long, stigma umbrella-shaped, 5-lobed nectar secreting disc present.
Fruit:
Drupe.
Economic Importance of Family – Apocynaceae:
The family is of little economic value. Some plants are grown as ornamentals, while some possess medicinal properties.
A list of some important plants is given here:
1. Alstonia scholaris; Eng.-Dita bark; Verna.-Satwin. This is a small tree grown as an ornamental. Its wood is quite light and used for carvings. In Myanmar, the black boards are prepared from its wood. The bark possesses medicinal properties, which is used for diarrhoea and dysentery. Its latex is applied to ulcers.
2. Beaumontia grandiflom; Eng.-Nepal trumpet flower-It is a climbing shrub, usually grown as an ornamental for its large, white fragrant flowers. It is native of the Eastern Himalayas.
3. Beaumontia jerdoniana; This is also grown as an ornamental.
4. Anodendron paniculatum; Its leaves and roots possess medicinal properties.
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5. Carissa carandas; Eng.-Karanda; Verna.-Karaunda-This is a spiny shrub grown throughout India for its sour edible fruits. The fruits are used as vegetable and pickle is prepared from them. The plant makes a good hedge.
6. Carissa grandiflora; Syn. Arduina grandiflora; Eng.-Natal plum.-This is a large spiny shrub usually grown in Maharashtra and Baroda for its edible fruits.
7. Carissa spinarum. This is a shrub or a small tree cultivated throughout India for fragrant flowers and hedge plants.
8. Carrisa arduina; Syn. C. bispinosa- Eng.-Natal plum.-This is a thorny shrub grown for its edible fruits.
9. Ichnocarpus frutescens; Eng. -blackcreeper; Verna.-Dudhilata, Siamalata. This is a twining ornamental shrub. It is found in Uttar Pradesh, Madhya Pradesh, Bihar, Assam and the Sundarbans. The stems are used for making ropes, baskets and fishing traps. The leaves possess medicinal properties.
10. Landolphia kirkii.-The rubber is prepared from its latex. They have leaves with hook tendrils.
11. Nerium indicum; Syn. N. odorum; N. oleander, Eng.-Oleander; Verna.-Kaner.-It is a shrub. They are grown as hedge plants. The plants possess medicinal properties.
12. Rauvolfia serpentine; Syn. Ophioxylon serpentinum; Verna.-Chhotachand.-This is a small shrub found in Assam, Dehradun, Bihar, the Western Ghats and Bengal; the roots possess medicinal properties and are used in the treatment of hypertension, mental disorders and related ailments.
13. Plumeria rubra forma acutifolia; Syn. P. acutifolia; Verna.-Goburchampa-It is grown as an ornamental. It possesses several medicinal properties.
14. Plumeria alba.-A small tree, grown as an ornamental. The latex is applied to ulcers.
15. Thevetia peruviana; Syn. Thevetia nerifolia; Eng.-Yellow oleander; Verna.- Pilikaner.- It is a shrub. The plants are grown as ornamental. They are also grown as hedge plants. The latex is highly poisonous.
16. Wrightia tinctoria; Syn. W. rothii; Nerium tinctorum; Verna.-Dudhi.-A tree, found in Rajasthan, Madhya Pradesh and Tamil Nadu. A blue dye is obtained from its flowers and fruits. The fruits are edible. The bark and seeds possess medicinal properties.
17. Wrightia tomentosa; Syn. W. mollissima; Nerium tomentosum; Verna.-Dharauli-The seeds and roots yield a yellow dye. The leaves and fruits are edible. Its soft wood is used for carvings. The bark and roots are used as an antidote for snake bite.
18. Aganosma dichotoma; Syn. Echites dichotoma; Verna.-Malati.-This is a climbing shrub, grown as an ornamental in the gardens.
19. Allamanda cathartica; Eng.-Allamanda-This is a beautiful climbing shrub, grown as an ornamental in the gardens. It is native of Central America and Brazil.
