The below mentioned article provides an overview on The Dicotyledone. After reading this article you will learn about: 1. Introduction to Dicotyledone 2. Explanation on Family-Rosaceae 3. Economic Importance of the Family-Rosaceae.
Introduction to Dicotyledone:
According to Hutchinson this is the sixth order of the phylum Angiospermae, subphylum Dicotyledones and division Lignosae. The order comprises of three families, i.e., Rosaceae, Dichapetalaceae and Calycanthaceae, of which the Rosaceae has been described here in detail.
Bentham and Hooker have placed this family together with other five families in their eleventh order-the Rosales of class Dicotyledones, division Polypetalae and series Calyciflorae. Engler and Prantl have also included the family Roscaceae with other seventeen families in their twenty first order-the Rosales of class Dicotyledoneae and sub-class Archichlamydeae.
Perigynous to epigynous, mostly apocarpous to syncarpous with central placentation; no endosperm; leaves simple to compound, stipulate.
Explanation on Family-Rosaceae:
This family consists of about 115 genera and 3,200 species (Lawrence).
Distribution:
Though the members belonging to this family are cosmopolitan, yet they are mainly distributed in temperate and colder regions. In India most of the genera have been reported from hilly regions. The family is represented in our country by the following few important genera, e.g., Prunus, Pyrus, Rubus, Rosa, Eriobotrya, Fragaria, Potentilla, etc.
Habit:
There are great variations in the habit of the plants included in this family. They may be trees shrubs or herbs. Very often they are thorny and sometimes climbing. Most of the species are herbaceous and wild, while on the other hand some species are grown for their delicious fruits, and as ornamentals.
Root:
Tap and branched.
Stem:
The stem is erect or creeping, herbaceous or hard and woody, cylindrical, branched; many shrubs are spiny (e.g., Rosa) in Rosa and Rubus these spiny outgrowths are cortical and arise from both nodes and internodes. Vegetative propagation takes place by means of runners, suckers and cuttings. The bud grafting is very common in this family.
Leaves:
The leaves are alternate (rarely opposite, e.g., in seedling stage of Prunus), simple or pinnately compound, petiolate, usually stipulate, the stipules are adnate to the petiole; the leaf base is conspicuous, small spines are often present on the rachis; the margins of the leaves are either serrated or entire.
Inflorescence:
There are great variations in different species. It may be corymb, corymbose, umbellate, racemose, or the flowers may be solitary or in the small groups in the twos or threes. Sometimes the inflorescence is compound raceme (panicled flowers).
Flower:
Usually hermaphrodite (bisexual) rarely unisexual (e.g., Spiraea aruncus, where the plants are dioecious), actinomorphic, regular (irregular in Parinarium and Parastemon) bracteolate.
It may be hypogynous (e.g., in Fragaria), perigynous (e.g., in Prunus) or epigynous (e.g, in Pyrus).
Calyx:
It consists of 5 sepals, which are connate at the base (gamosepalous); basal portions are usually adnate forming a hypanthium; the lobes of the calyx are free, valvate or imbricate and green; sometimes the epicalyx is formed by bracteoles; the lobes of epicalyx remain alternate to the sepals.
Corolla:
It consists of 5 petals (rarely four petals) which are polypetalous; the petals usually arise from the rim of hypanthium; imbricate, very often the hypanthium bears a nectariferous glandular disc. The number of petals increases sufficiently in cultivated varieties because of the conversion of the stamens into petals. They are variously coloured. Sometimes the corolla is altogether absent (i.e., in Alchemilla, Poterium, etc.).
Androecium:
Usually the number of stamens is indefinite (15-60), sometimes they are 5-10, the stamens are generally arranged in one to many whorls of five each; they are perigynous around the gynoecium and arise from the hypanthium, free; the anthers are small, dithecous (two-celled), introrse and dorsifixed; the dehiscence takes place by means of longitudinal splits; the filaments are usually incurved in bud.
Gynoecium:
The number of carpels is one to many; the gynoecium consists of either one compound carpel (syncarpous) or many simple carpels (apocarpous) arranged in cyclic or spiral way.
The carpels are usually situated within the hypanthium or the hypanthium remains adnata to the compound ovary; the ovary is either superior or inferior or half superior half inferior (i.e., perigynous condition), when syncarpous, 2-5 locules are found, the placentation is axile, and the stigmatic lobes are as many as the number of carpels.
The placentation is basal when one carpel is present (apocarpous); the ovules are one to many in each carpel. The style is free or connate, the stigma is simple, lobed or capitate.
Fruit:
They may be dry or fleshy. It may be a pome (e.g., in Pyrus), pyriform berry (e.g., in Eriobotrya), an etaerio of achenes (e.g., in Rubus), or one seeded drupe (e.g., in Prunus), etc.
Seeds:
The seeds are exalbuminous, generally with small embryo.
Pollination:
The pollination takes place usually through the agency of insects (i.e., entomophily), but sometimes there is wind pollination (i.e., anemophily).
Floral Formula:
Description of some important plants in semi-technical language:
Prunus Persica; Verna. Aru. (See fig. 14.3).
Habit:
Either shrubs or small trees, usually grown in the gardens for their delicious fruits.
Root:
Tap and branched.
Stem:
Erect, branched, woody, cylindrical and glabrous.
Leaf:
Alternate, simple, stipulate, petiolate, entire or toothed, very frequently two glands present on the petiole. In Prunus persica the leaves are oblong-lanceolate or oblong oblanceolate, 4 to 6 inches long, finely serrate, short petioles, fimbriate stipules.
Inflorescence:
Flowers are solitary or in fascicles, corymbose or racemose.
Flower:
Bisexual (hermaphrodite), pedicellate (small pedicels), actinomorphic, regular, perigynous, complete, pink.
Calyx:
Five sepals, gamosepalous, sepaloid, imbricate, deciduous in fruit, calyx-tube bell shaped, 5-lobed, inferior.
Corolla:
5 polypetalous (petals free), petals large, arranged on hypanthium, conspicuous, pink, inferior.
Androecium:
Stamens indefinite (15-60), perigynous, inserted on the hypanthium, anthers bi- celled, dorsifixed, reddish or brown, dehiscence by longitudinal split, introrse, filaments free.
Gynoecium:
One carpel (monocarpellary), ovary situated within the hypanthium (calyx tube), ovary unilocular, with two pendulous ovules, style terminal, stigma broad.
Fruit:
Single seeded drupe, fleshy, enclosing an indehiscent or two valved furrowed stone.
Seeds:
Exalbuminous, pendulous.
Generic Characters:
Ripe carpels not enclosed within the calyx tube (hypanthium), carpels free; carpel one, fruit a drupe with a hard furrowed stone; shrubs or trees with simple leaves; calyx 5 lobed, petals large.
Floral Formula:
Eriobotrya Japonica:
Verna-Lokat.
Habit:
Small trees, grown in the gardens for their edible fruits.
Root:
Tap and branched.
Stem:
Erect, woody branched with stout branches, cylindrical.
Leaves:
Simple, alternate, entire, serrate or crenate, coriaceous; in Eriohotryajaponica, the leaves are large, 6-12 inches long, sub-sessile, lanceolate, or oblanceolate, acuminate, dentate or serrate, net veined, and wooly below.
Inflorescence:
Flowers arranged in dense panicles, the inflorescence is wooly.
Flower:
Pedicellate (short pedicels), actinomorphic, regular, hermaphrodite (bisexual), epigynous, yellowish white in colour, bracteate and bracteolate.
Calyx:
5 sepals, gamosepalous, small persistent, arranged on the turbinate or clavate hypanthium, sepals also wooly.
Corolla:
5 petals, free, polypetalous contorted or imbricate in bud, obovate or orbicular, usually oblique and notched at margins, claw glabrous and wooly, yellowish white in colour.
Androecium:
Indefinite in number, stamens curved inward in the bud, filaments free, anthers 2-celled, dorsifixed, dehiscing longitudinally, introrse.
Gynoecium:
Carpels enclosed in the hypanthium, 2-5 celled ovary, with connate and wooly below styles, each cell contains two ovules, axile placentation.
Fruit:
Succulent or dry; in E japonica, the fruit is ovoid, yellow, succulent and pyriform berry, 1-1.5 inches long. 1-5 seeded.
Seed:
Exalbuminous, large and angled with thick cotyledons.
Generic Characters:
Carpels definite, 2-ovuled, enclosed in the hypanthium, and adnate to its walls, more or less connate with one another to form a syncarpous ovary; fruit a berry or pome; flowers arranged in panicles.
Malus Sylvestris; Verna. Seb:
Habit:
Small tree or large shrub.
Stem:
Erect, woody, branched, cylindrical, solid.
Leaves:
Simple or pinnate, deciduous, petiolate, stipulate (stipules deciduous), glabrous, acute, ovate, unicostate reticulate venation.
Inflorescence:
Cymose, terminal cymes or corymbs.
Flower:
Pedicellate, bracteate (bracts linear), bracteolate (two bracteoles), hermaphrodite, actinomorphic; complete, epigynous.
Calyx:
Five sepals, gamosepalous, calyx-tube obconical lobes erect or reflexed, persistent or deciduous.
Corolla:
Five petals, polypetalous, quincuncially imbricate in bud.
Androecium:
Indefinite stamens (20 or more), filaments long, connate at the base, anthers dorsifixed, introrse; dehisce longitudinally.
Gynoecium:
Two to five carpels, connate and adnate to calyx-tube, syncarpous, ovary inferior, 2-5 locular, axile placentation, styles 2-5, free or connate below, stigmas truncate; ovules 2 in each loculus.
Fruit:
A pome, fleshy.
Floral formula:
Potentilla Supina:
Habit:
Perennial herbs, rarely shrubs.
Stem:
Erect or diffusely spreading, branched, woody or herbaceous, pubescent, cylindrical, solid.
Leaves:
Compound, petiolate stipulate (stipules adnate to the petiole), leaflets mostly serrate, reticulate venation.
Inflorescence:
Cymose, solitary or corymbose cymes.
Flower:
Pedicellate, hermaphrodite, actinomorphic, complete, hypogynous, white or yellow rarely red.
Calyx:
Five sepals, rarely four sepals, persistent, valvate in bud.
Epicalyx:
Five bracteoles, rarely four bracteoles, alternating with sepals.
Corolla:
Five petals, rarely four petals, white, yellow or rarely red, polypetalous.
Androecium:
Indefinite stamens, rarely few (5 – 10).
Gynoecium:
Many carpels (polycarpellary), on a small dry receptacle, ovary superior with single ovule, style persistent or deciduous, lateral, short, stigma minute.
Fruit:
An etaerio of achenes.
Floral formula:
Rosa indica; Verna-Gulab:
Habit:
Erect or climbing perennial shrubs, usually prickly.
Root:
Tap, branched.
Stem:
Erect, branched, prickly, solid, woody, cylindrical.
Leaf:
Compound, imparipinnate, petiolate, stipulate (stipules adnate to the petiole), leaflets serrate, ovate, acute, unicostate, reticulate venation.
Inflorescene:
Cymose, flowers terminal, solitary.
Flower:
Pedicellate, bracteate (bracts rarely persistent), hermaphrodite, actinomorphic, complete, perigynous, white, yellow, red or pink.
Calyx:
Five sepals, gamosepalous, narrowly lanceolate, inferior, quincuncial aestivation, calyx-tube persistent, globose ovoid or pitcher shaped.
Corolla:
Five to indefinite petals, polypetalous large, showy, scented, imbricate aestivation in bud.
Androecium:
Stamens many, inserted on the disk, polyandrous, inferior, petals are modified into stamens, anthers bicelled, introrse.
Gynoecium:
Many carpels, apocarpous, found in the bottom of calyx-tube, styles subterminal, free or connate above, stigma thickened, ovule one, basal placentation.
Fruit:
An etaerio of achenes.
Floral formula:
Economic Importance of the Family-Rosaceae:
Economically this family is of much importance, containing various types of valuable fruit plants. Several other plants are ornamental and are planted in the gardens, public places and houses for their beautiful and fragrant flowers.
A list of some important plants is given here:
1. Prunus persica; Syn. Amygdalus persica; Persica vulgaris; Eng.-Peach; Verna-Aru-This is native of China, but now cultivated in Kashmir, the hills of the Punjab, Himachal Pradesh, Kulu and Kumaon.The fruits are edible and rich in vitamins; the oil is obtained from the seeds which is used for cooking and other purposes.
2. Prunus domestica subs, insititia; Syn. Prunus communis var. insititia; Eng.-Plum; Verna- Alucha, Alu-bokhara-This is cultivated in the hills of Kashmir, Punjab, Himachal Pradesh, Kulu and Kumaon for the edible vitaminized fruits.
3. Prunus amygdalus; Syn. P. communis; Amygdalus communis; Eng.-Almond; Verna. Badam-This is a tree. This is native of the East mediterranean region but now chiefly cultivated in the Punjab and Kashmir for the edible seeds. There are two varieties of almonds, i.e., sweet and bitter. The oil obtained from the seeds of both the varieties is used in perfumery and medicinal purposes.
4. Prunus armeniaca; Syn. Armeniaca vulgaris; Eng. Apricot; Verna.-Khubani, Zardalu. This is native of Asia, now cultivated in Kashmir, Kulu, Kumaon and Himachal Pradesh. The fruits are edible and rich in vitamins.
5. Prunus avium’, Eng.-Sweet cherry; Verna. Gilas-This is native of Eurasia but now cultivated in Kashmir, Kulu, Kumaon and Himachal Pradesh for their delicious edible fruits.
6. Prunus cerasus; Eng.-Sweet cherry; Verna. Aiubalu, Gilas.-This is native of Eurasia, but now cultivated in the Punjab, Kashmir, Himachal Pradesh and Kumaon hills. The fruits are edible.
7. Prunus cerasoides; Syn. P. puddum; Eng. Wild Himalayan cherry ; Verna. Paddam- They are commonly found in the temperate Himalayas from Garhwal to Sikkim and also in Nilgiris. The fruits are edible. The stones (i.e., endocarp) are made into rosaries and necklaces, and the wood is used for walking sticks.
8. Prunus salicina ; Syn. P. triflora ; Eng.-Japanese plum. This is native of China but now grown in the Nilgiris. The fruits are edible.
9. Prunus padus: Syn. Padus avium; Eng.-European birdcherry; Verna.-Jamana. This is found in the temperate Himalayas. The fruits are edible.
10. Prunus jenkinsii; Syn.-Cerasus jenkinsii. This is found in Assam and the Khasia hills. The fruits are edible.
11. Eriobotrya japonica; Eng.-Loquat; Verna.-Lokat. This is a small tree. It is native of China, now chiefly cultivated in Uttar Pradesh and the Punjab for the edible fruits.
12. Fragaria vesca; Eng.-Perpetual strawberry . This is native of Europe but now cultivated in Himachal Pradesh, Assam, Kulu, Kumaon and Maharashtra. The fruits are edible.
13. Fragaria nilgerrensis; Eng.-Houtbois strawberry. This is found in the Khasia hills and Nilgiris. The fruits are edible.
14. Fragaria chiloensis; Eng.Garden strawberry. This is a herb, cultivated in Kumaon, Kulu and Himachal Pradesh for the edible fruits.
15. Duchesnea indica; Syn. Fragaria indica; Eng.-Indian strawberry; Verna-Kiphaliya.- This is a perennial herb, commonly found in the temperate Himalayas, the Punjab, Assam, the Khasia hills and the Nilgiris. The fruits are edible.
16. Pyrus communis; Eng.-Pear; Verna.-Nakh,-This is a small tree. It is native of Eurasia but now cultivated in Kashmir, Kulu, Kumaon and Himachal Pradesh. The fruits are edible.
17. Malus sylvestris; Syn. Pyrus malus; Malus pumila; Eng.-Apple; Verna-Seb.-This is a small tree; native of Eastern Europe and Western Asia but now cultivated in Kashmir, Himachal Pradesh, Kulu, Kumaon, Assam and in the Nilgiris. The fruits are edible, delicious, rich in iron and vitamins.
18. Malus baccata; Syn. Pynis baccata; Eng.-Siberian crab apple; Verma Jangli Seb-This is a small tree, cultivated in Kashmir and the Khasia hills. It is used as a stock for apple. The fruits are eaten as vegetable.
19. Docynia indica; Syn. Pyrus indica; Eng.-Indian crab apple.-This is a tree found in the Eastern Himalayas and the Khasia hills. The fruits are edible.
20. Pyrus pashia; Verna.-Mehal-This is commonly found in the Western Himalayas. It is used as a root stock for pear. The wood is used in making walking sticks and tobacco pipes.
21. Pyrus pyrifolia var. culta; Eng.-Chinese pear; Verna.-Nashpati-This is native of China but now cultivated in Kashmir, Assam, Kumaon, Darjeeling, the Nilgiris, Himachal Pradesh and Delhi for the edible fruits.
22. Pyrus vestita; Verna.Mauli-This is found in the Eastern Himalayas and the Khsia hills. The fruits are edible.
23. Sorbus aucuparia; Syn. Pyrus aucuparia; Eng. European mountain ash; Verna.-Battal- This is a tree. It is native of Eurasia but now found in the temperate Himalayas from Kashmir to Kumaon. The fruits are edible.
24. Spiraea cantoniensis ; This is a native of China and Japan. This is a small herb grown as an ornamental.
25. Spiraea corymbosa-This is a small shrub, grown in the gardens as an ornamental.
26. Rubus fruticosus; Eng. European black berry; Verna.-Vilayati-anchu-This is cultivated in Kashmir, Assam and Conoor for the edible fruits.
27. Rubus ellipticus; Eng. Himalayan yellow raspberry; Verna.-Lal anchu, Hisalu-This is a shrub found in the Western Himalayas, South India, the Western ghats and the Khasia hills. The fruits are edible.
28. Rubus rosaefolius; Eng. Mauritius raspberry; Verna.-Yeshul-This is cultivated in Kumaon, the Khasia hills and Manipur. The fruits are edible.
29. Rubus lanatus; Verna.-Hisalu-This is found in Kumaon. The fruits are edible.
30. Rubus lasiocarpus; Eng. Ceylon Raspberry; Verna.-Kala anchu, Kala hisalu-This is found in the Western Himalayas, Sikkim, the Khasia hills, the Western Ghats, Karnataka and the Pulney hills. The fruits are edible.
31. Rubus moluccanus; Eng. Black cherry; Verna-Katsol.-This is found in Assam, the Khasia hills the Nilgiris and Travancore. The fruits are edible.
32. Rosa alba; Eng. Indian white rose ; Verna-Gulab, Gulchini-This is a herb, grown as an ornamental in the gardens.
33. Rosa chinensis; Syn. Rosa indica ; Eng. Edward rose; Verna.-Cheenia gulab, Desi Gulab-This is chiefly cultivated in the Kanauj, Kanpur and Hathras regions of Uttar Pradesh. The petals are the sources of rose water, essential oil, pankhuri and gulkand.
34. Rosa centifolia; Eng. Cabbage rose; Verna-Gulab-This is a herb or small shrub. This is cultivated mainly in the Uttar Pradesh and Bihar. The petals yield an essential oil which is used in perfumery and cosmetics.
35. Rosa damascena: Eng. Damask rose; Verna-Gulab-They are cultivated chiefly in Aligarh, Ghazipur and Kanauj of Uttar Pradesh. An essential oil known as ‘otto of roses’ or ‘oil of roses’ obtained from the petals is used in perfumery. The other important rose products are-rose water, attar, gulkand, pankhuri. Gulkand is used as a tonic and laxative. The dried rose petals are known as pankhuri which are used for preparing cold drinks.
36. Rosa banksiae: Eng. Banksia rose-This is climbing herb. This is native of China. It is grown as an ornamental in the gardens.
37. Crataegus oxycantha; It is found in the Himalayas from 6,000 feet to 9,000 feet elevation a.s.l. The wood is hard and, therefore, is used in making tool handles.
38. Potentillafruticosa-This is a small herb. The leaves possess medicinal properties and are used as substitute for tea.
39. Potentilla nepalensis-this is medicinal plant; used as a remedy of burns.
40. Potentilla reptans-The infusion of the herb is used as a remedy of diarrhoea.
41. Cotoneaster acuminata; Verna-Riu-This is a shrub found in Himalayas. The wood is used for making walking sticks.
42. Chrysobalanus icaco: Eng. Coco plum-This is a shrub or small tree, introduced into Malabar. The fruits are edible.
43. Cydonia oblonga; Syn. Cydonia vulgaris; Verna-Bihi-This is a small tree. It is native of West Asia, now grown in Punjab, Kashmir and the Nilgiris for the edible fruits. It is used as a root-stock for pear.
Systematic Relationships:
According to Engler the order Rosales consists of about twenty families. Among these families there are very few points of similarity. Hutchinson has splitted the order into a number of distinct orders.