The below mentioned article provides an overview on Euphorbiales; Family—Euphorbiaceae. After reading this article you will learn about: 1. Introduction to Euphorbiales 2. Family—Euphorbiaceae 3. Economic Importance of the Family – Euphorbiaceae.
Contents
Introduction to Euphorbiales:
According to Hutchinson this is the thirty fifth order of the phylum Angiospermae, sub phylum Dicotyledones and division Lignosae. The order consists of a single family, i.e., the Euphorbiaceae which has been described in the present text in detail.
Bentham and Hooker have included the Euphorbiaceae along with other eight families including Urticaceae and Casuarinaceae in their seventh series—the Unisexuales of class Dicotyledones, and division Monochlamydeae or Incomplete.
Engler and Prantl have included the family Euphorbiaceae along with other nineteen families including Linaceae, Rutaceae and Meliaceae in their twenty third order—the Geraniales of class Dicotyledoneae and sub-class Archichlamydeae.
Hypogynous; actinomorphic; unisexual; petals usually absent, if present sometimes quite sympetalous (Jatropha)-, syncarpous with 1-2 ovules pendulous from the inner angle; stamens various; seeds often with a conspicuous caruncle; endosperms mostly copious; stipules mostly present.
Family—Euphorbiaceae:
There are about 283 genera and 7,300 species in this family.
Distribution:
The plants of this family are found throughout the world. However, they are not found in arctic regions. In our country the family is represented by several genera such as, Euphorbia, Ricinus, Phyllanthus, Croton, Pedilanthus, etc. In the desert regions of Africa and elsewhere the family is represented by cactus-like plants of different species of Euphorbia.
Heath like Euphorbias are quite common in Australia. In Britain only two genera, i.e., Euphorbia and Mercurialis are found, which are represented by sixteen and two species respectively.
Habit:
The plants exhibit great variation in their habit. The plants may be herbs, shrubs or trees. Euphorbia hirta, E. thymifolia, E. helioscopica, E. peplus; E. heterophylla, E. cristata, E. elegans; Phyllanthus niruri, Croton sp., Acalypha indica, etc., are annual or prennial herbs. Euphorbia pulcherrima, E. splendens, are beautiful shrubs. Pedilanthus sp., and Jatropha sp., are shrubby plants.
Euphorbia royleana, E. tirucalli are cactus like shrubs. Ricinus communis (Arand) is a tall annual and becomes small tree-like in habit. The tree habit of the family is represented by Phyllanthus emblica (Amla), Bischofia javanica, Putranjiva roxburghii, etc.
Havea brasiliensist (rubber tree) is a large tree 60 to 100 feet in height and 8-12 feet in girth. Species of the genus Tragia are tropical climbers. Majority of the members of the family possess large laticiferous vessels which contain latex.
Root:
Tap and branched. The roots of Manihot utilissima and M .palmata are tuberous and rich in starch.
Stem:
Herbaceous or woody, erect, very rarely climbing as in a tropical genus Tragia. The species of Xylophylla possess flat phylloclades. The stem is branched. It may be cylindrical, angular or flat. Usually solid but sometimes hollow as in Ricinus communis. Many stems possess spines. In many Euphorbia sp., the stems become fleshy, green and cactus like in appearance.
Leaves:
The form and position of leaves are variable. The arrangement is usually alternate but sometimes they are opposite, e.g., Euphorbia hirta. In Pedilanthus the leaves are arranged alternately in the lower region of the plant whereas opposite in the floral region.
Usually the leaves are simple but in some they are deeply incised, e.g., Ricinus, Manihot, etc. In many Euphorbias the leaves are scaly and caducous. In many cases the leaves are reduced to spines. In few cases the leaves are replaced by cladodes. Usually the leaves are stipulate. In Jatropha sp., the stipules become branched and hair-like. In many Euphorbia sp., they are represented by glands or spines.
Inflorescence:
The inflorescence varies greatly. It may be racemose or cymose or sometimes complex. In Euphorbia, the inflorescence is peculiar but very characteristic and known as cyathium. This is the modification of a cyme. In cyathium inflorescence a large number of male flowers each represented by a stalked stamen are found arranged around a central stalked female flower. The female flower consists of gynoecium only.
The complete inflorescence looks like a single flower. The bracts are being arranged like a perianth. The bracts are so united that they form a cup-like structure. In Acalypha the inflorescence is catkin type. In Croton and Ricinus the flowers are arranged in terminal racemes. In Jatropha the inflorescence is of cymose type and the flowers are arranged in terminal cymes. In Manihot the flowers are being arranged in racemes.
Flowers:
The flowers are always unisexual. They are much reduced and may be monoecious or dioecious. In Euphorbia sp., each male flower is represented by a single stalked stamen. The flowers are incomplete, regular, actinomorphic and hypogynous.
Perianth:
Occasionally, both calyx and corolla are present, e.g., Croton. In majority of cases either calyx or corolla or both are absent. In Ricinus communis the calyx is present and the corolla absent. In Euphorbia hirta both the whorls of calyx and corolla are absent. In Jatropha sp., both calyx and corolla are present.
In Acalypha indica the perianth is represented by four minute sepaloid petals. In Phyllanthus only sepaloid perianth is present. In Euphorbia the perianth is absent or represented by tiny scaly structures.
The perianth consists of 4 to 5 petals. The calyx and corolla consists of 4 or 5 sepals or petals. The aestivation is valvate or imbricate.
Androecium:
The number of stamens varies from one to many. Usually as many stamens are present as many perianth leaves. In Euphorbia a single stalked stamen represents a single male flower. In Ricinus sp., usually five stamens are present, each stamen is profusely branched. In Jatropha they are arranged in two whorls each of five stamens.
In many the stamens are indefinite, e.g., Croton. The filaments may be free or united. The anthers are dithecous. They dehisce either by apical pores or by transverse or longitudinal slits.
Gynoecium:
Three carpels (tricarpellary), syncarpous; the ovary is trilocular, superior. Each locule contains one or two pendulous, anatropous ovules. The placenation is axile.
Fruit:
The fruits are schizocarpic. The fruits break violently and dehisce into one seeded cocci. Such type of fruit is termed regma which is characteristic of Ricinus sp. The sp., of Trewia and Bridelia bear drupe fruit. Phyllanthus emblica also bears drupe.
Seeds:
The seed is endospermic. In Ricinus caruncle develops from the micropyle. The cotyledons either lie flat or are folded within the endosperm.
Pollination:
Usually entomophilous, i.e., through the agency of insects. Only cross- pollination takes place. In many species the leaves and bracts become coloured and showy to attract the insects. Sometimes anemophily is also found.
Floral Formulae:
The floral formulae of different genera are as follows:
A few important plants have been described here in semi-technical language:
1. Ricinus communis; Eng.-Castor oil plant; Verna.- Arand:
Habit:
Tall annual or perennial shrub or small tree.
Root:
Tap and branched.
Stem:
Erect, cylindrical, branched, solid, and glabrous.
Leaf:
Alternate, simple, petiolate, broad, palmately lobed, lobes usually 7-9, serrate, multicostate reticulate venation.
Inflorescence:
Terminal panicled cyme.
Flower:
Pedicellate, ebracteate, unisexual, monoecious, male flowers towards lower portion, female flowers towards apical portion of inflorescence, actinomorphic, incomplete, hypogynous.
Male Flowers:
Calyx:
5 or 4, membranous, polysepalous, green, inferior, valvate aestivation.
Corolla:
Absent.
Androecium:
5 stamens, each stamen profusely branched, anther cells borne on ultimate branchlets, anthers basifixed.
Female Flowers:
Calyx:
3 to few or more, membranous, caducous, spathaceous, valvate aestivation.
Corolla:
Absent.
Gynoecium:
3 carpels (tricarpellary), syncarpous, ovary superior, trilocular, covered with spiny outgrowths, axile placentation, single large ovlue in each locule, three styles, three bifid stigmas.
Fruit:
A schizocarpic capsule or regma, splitting into three cocci, spiny outgrowths on fruit.
2. Euphorbia hirta:
Habit:
Annual wild herb.
Stem:
Erect, usually un-branched (sometimes branched), herbaceous, cylindrical, solid, covered with yellow crisped hairs.
Leaf:
Simple, opposite, superposed, sub-sessile (short petiole), acute, oblong, lanceolate, serrulate, stipulate, stipules caducous, unicostate reticulate venation.
Inflorescence:
Large number of cyathia densely crowded and arranged in peduncled axillary cymes.
Flowers:
Pedicellate, unisexual, monoecious, enclosed within minute involucre of bracts forming cupular structure.
Male Flower:
Perianth:
Absent, naked flower.
Androecium:
Single stalked stamen representing male flower, bracteate, anthers 2-celled dehiscing longitudinally.
Female Flower:
Perianth:
Absent, naked flower.
Gynoecium:
A single stalked, bracteate, tricarpellary pistil represents female flower, it remains surrounded by male flowers (stalked stamens), ovary superior, three-chambered, single ovule in each loculus, axile placentation, three styles, three bifid stigmas.
Fruit:
A capsule.
3. Croton sparciflorus:
Habit:
Annual wild herb.
Stem:
Erect, herbaceous, branched, rough, latex present, solid, cylindrical.
Leaf:
Alternate, simple, petiolate, exstilpulate, serrate margin, acute, rough, unicostate reticulate venation.
Inflorescence:
Racemose, raceme, male flowers on the upper portion, female flowers on the lower portion of inflorescence.
Flower:
Pedicellate, bracteate, unisexual, monoecious plant, actinomorphic, incomplete, hypogynous, glands present.
Male Flower:
Calyx:
5 sepals, polysepalous, persistent, imbricate.
Corolla:
5 petals, polypetalous, 5 glands opposite sepals, valvate aestivation.
Androecium:
Stamens many, inserted on receptacle, filaments free, incurved in bud, anthers adnate.
Female Flower:
Calyx:
As in male flowers.
Corolla:
Absent.
Gynoecium:
3 carpels (tricarpellary), syncarpous, 3 styles ending in 3 bifid stigmas, ovary superior, three chambered, single ovule in each loculus, axile placentation.
Fruit:
Indehiscent capsule.
4. Phyllanthus reticulate; Verna. Panjoli:
Habit:
An annual herb.
Stem:
Erect, branched, herbaceous, green, solid, cylindrical 1/2 to 2 feet in height.
Leaf:
Simple, alternate, sub-sessile, elliptic-oblong, rounded obtuse, glaucous beneath, stipulate, distichous often resembling pinnate compound leaves, 1/4 – 1/2 inch long.
Inflorescence:
Axillary flowers.
Flower:
Minute, unisexual, trimerous, actinomorphic, bracteate, shortly pedicellate.
Male flower:
Perianth:
6 petals (perianth leaves), arranged in two whorls of three each, polyphyllous, sepaloid, imbricate aestivation, disc of minute glands inside the perianth.
Androecium:
3 stamens, polyandrous, filaments short, borne on a short column.
Female Flower:
Perianth:
As in male flower.
Gynoecium:
3 carpels (tricarpellary), syncarpous, ovary superior, three chambered, each loculus having two ovules, axile placentation, stigma trifid.
Fruit:
Schizocarpic regma, opening into three cocci.
5. Acalypha indica:
Habit:
An annual herb.
Stem:
Erect, branched, herbaceous, solid cylindrical, hairy.
Leaf:
Alternate, long petiolate, stipulate, rhomboid ovate, serrate obtuse, multicostate reticulate venation.
Inflorescence:
Racemose, axillary spikes, male flowers towards the apex of spike, female flowers towards lower portion of spike in clusters of 3-5 subtended by a leafy bract.
Flower:
Sessile, unisexual, monoecious plant, male flower ebracteate, female flower bracteate, minute incomplete, hypogynous.
Male Flower:
Perianth:
4, minute sepaloid perianth leaves, polyphyllous, valvate aestivation.
Androecium:
8 stamens, polyandrous, filaments short.
Female Flower:
Perianth:
3 – 4 sepaloid perianth leaves, polyphyllous, imbricate aestivation.
Gynoecium:
3 carpels (tricarpellary), syncarpous, ovary superior, 3-chambered, axile placentation.
Fruit:
Capsule, often one seeded.
6. Jatropha gossypifolia L. Vernat Bherenda:
Habit:
A cultivated shrub.
Stem:
Erect, branched, solid, cylindrical, woody, hairy, gland dotted.
Leaf:
Simple, alternate, cauline, petiolate, petiole spiny, stipulate, stipules spiny, entire, acuminate, bright green on dorsal side, greenish violet on ventral side, unicostate reticulate venation.
Inflorescence:
Cymose, polychasial cyme.
Flowers:
Monoecious, actinomorphic, unisexual, incomplete, bracteate.
Calyx:
5 sepals, gamosepalous, petaloid, reddish green, valvate.
Corolla:
5 petals, polypetalous, twisted aestivation.
Androecium:
10 stamens, arranged in two whorls of five each, monadelphous, anthers dorsifixed.
Female Flowers:
Pedicellate, bracteate, unisexual, incomplete, hypogynous.
Calyx:
As in male flower.
Corolla:
As in male flower.
Gynoecium:
3 carpels (tricarpellary), syncarpous, ovary superior, three-chambered, axile placentation, three styles, three bifid stigmas.
Fruit:
Three valved capsule.
7. Euphorbia pulcherrima:
Euphorbia pulcherrima willd., Eng. Poinsettia; Verna. Lal patta. Stem- herbaceous or woody, aerial, erect, branched, solid cylindrical, latex present. Leaf-cauline and ramal, simple, aternate, extipulate, petiolate, ovate, entire, acute, glabrous, latex present, unicostate reticulate.
Inflorescence-special, cyathium, bracts red and leaf-like, male flowers surround the female flower. Male flower-represented by a single jointed stamen, anther dithecous, basifixed introrse.
Female flower – represented by a tricarpellary stalked gynoecium, syncarpous, superior, trilocular, one ovule in each locule, axile, style short, stigmas 3 bifid. Fruit-capsule.
Economic Importance of the Family – Euphorbiaceae:
The family consists of the plants of great economic value. Some of the important ones are given below:
1. Acalypha hispida; An ornamental herb.
2. Acalypha wilkesiana- (Eng. -Garden Acalypha). Grown in the gardens as ornamental plant.
3. Bischofia Javanica; (Eng.-Bishop wood; Verna-Bhillar)- A tree. A red dye, obtained from the bark is used to stain rattan baskets. The bark is also used as a tan. The wood is extremely resistant to water effect and therefore, largely utilized in the construction of bridges and boats.
4. Bridelia retusa, (Verna.-Ekdania, Khaja)-A tree, found in Rajasthan, Madhya Pradesh, the Western Peninsula and Bihar. The bark is used for tanning. The fruits are edible and the leaves are used as fodder.
5. Cleistanthus collinus’ (Verna-Garari)-A small tree, found in Tamil Nadu, Malabar, Bihar, Orissa and Madhya Pradesh. The bark, leaves and green fruits are used as tan.
6. Croton aromaticus; An aromatic shrub or small tree found in Andhra Pradesh produces a gum-resin, which is used in varnishes.
7. Croton oblongifolius; (Verna-Chuka) – The seeds yield an oil, which is used as a purgative and also as an insecticide.
8. Croton tigllium; (Verna-Jamalgota)-A shrub or small tree, native of South East Asia but cultivated in Assam, Bengal and South India. The seeds are the source of croton oil, which is used as a purgative.
9. Baccaurea courtallensis: Found in the Western Ghats. The fruits are edible.
10. Baccaurea sapida- (Verna-Lathua)-Found in Assam, Bengal and Andaman Islands The fruits are edible.
11. Chrozophora prostrata (Verna-Subali)-The root ashes are given to the children for cough treatment. The seeds are used as a purgative.
12. Baliospermum montanum; (Verna-Danti)-The seeds are used as a strong purgative. The decoction of leaves is used in asthma.
13. Euphorbia milii; Syn. E. splendens; A small climbing shrub; native of Madagascar. Grown in gardens as ornamental.
14. Euphorbia pulcherrima-, Syn. Poinsettia pulcherrima’, Eng-Poinsettia; (Verna.-Lal Patta)-A shrub, native of Central America. Grown as an ornamental.
15. Euphorbia tirucalli, (Verna.-Tohar)-Succulent spineless small tree, native of Africa. The roots are used for poisoning fish and birds.
16. Euphorbia hirta, (Verna.-Dudhi)-The plant is of medicinal value and used in many diseases of children and adults.
17. Euphorbia thymifolia; (Verna.-Chhoti dudhi)–The juice of leaves and seeds is used as a strong purgative. The juice is also used for remedy of ringworms and other skin diseases. It is an antidote for snake bite.
18. Euphorbia royleana- (Verna.-Thar)-The plants are used in hedges. The latex is used medicinally in several ways.
19. Euphorbia antiquorum- (Verna.-Tridhara, sehund)-The decoction of stem is used as a remedy of gout. The juice of the plant is also used as a strong purgative. The root bark is also used as a purgative.
20. Glochidion zeylanicum; (Verna.-Kumbalm)-The leaves are used in itches.
21. Securinega leucopyrus; Syn. Phyllanthus leucopyrus; Flueggea leucopyrus (Verna.- Hartho)-A large shrub or small tree, found in Uttar Pradesh, the Punjab, Maharashtra and Tamil Nadu. The fruits are edible.
22. Jatropha curcas; (Verna.-Safed arand)- A shrub or small tree, native of tropical America, now cultivated in Travancore. The seed oil is used for manufacturing candles, soaps and as a lubricant and for illumination. The seed oil is also used as a purgative. The tender shoots are edible. Oil also used as biodiesel.
23. Jatropha gossypifolia; (Verna.-Bherenda)-A shrub, native of Brazil. Cultivated as an ornamental.
24. Jatropha hastate; Grown as an ornamental for bright crimson flowers.
25. Jatropha padagrica; (Eng.-Gouty stemmed Jatropha)-Native of Panama, grown for its bright scarlet flowers.
26. Manihot esculenta; Syn. M. utilissima; (Eng.-Tapioca; Verna.-Sakarkand)- A small shrub; native of Brazil, now grown in Kerala, Tamil Nadu and Karnataka. The tapioca tubers are exploited commercially to obtain starch, sago, semolina and flour.
27. Hevea brasiliensis; (Eng.-Para rubber; Verna.-Rabar) – A tall tree; native of Brazil;, now grown in Kerala, Tamil Nadu, Karnataka and North-Eastern Assam. The latex, obtained from the bark of the tree, is used for preparing rubber, which is used for tyres and inner tubes, waterproof clothing and various electrical goods.
28. Mallotus philippinensis- (Verna.-Kamala, Rauni)-A small tree found commonly in Bengal, Madhya Pradesh, Maharashtra and Orissa. The red dye, obtained from the surface of the fruits, is used for dyeing silk. Also used medicinally to remove thread worms and Ascaris.
29. Cicca acida; Syn. Phyllanthus acidus; Averrhoa acida; (Eng.-Stargoose-berry; Verna.- Hariphul)- A small tree cultivated in Bengal and South India for the edible fruits. The leaves are edible. The bark is used as a tan.
30. Emblica officinalis; Syn. Phyllanthus emblica; (Verna.-Amla)- A common tree with edible fruits. The fruits are also used in diarrhoea and dysentery. The bark, leaves and fruits are used in dyeing and tanning. The wood yields excellent charcoal. The pickle or jam is prepared from the fruits. The fruit is very rich in vitamin C.
31. Emblica fischeri; A small tree, found in South India. The fruits are edible.
32. Kiganelia reticulate; Syn. Phyllanthus reticulatus; (Verna.-Panjoli)- A climbing shrub, commonly found in Northern India. The roots are the source of a red dye.
33. Putranjiva roxburgii, (Eng.-Child-life tree; Verna.-Putranjiva)-A tall tree, grown as a hedge plant. The nuts are made in rosaries. The Hindus believe that if the hard stones of the fruits are made into rosaries and placed around the neck of the children, they keep them in good health.
The seeds also yield an oil which is used for burning purposes. The leaves are used as fodder. The leaves, fruits and stone of fruits are used medicinally in colds and fevers.
34. Ricinus communis; (Eng.-castor-oil plant; Verna-Arand)-A small tree, cultivated chiefly in Andhra Pradesh, Maharashtra, Karnataka and Orissa. The seeds are the source of castor-oil, which is mainly used as a lubricant and as a purgative. It is also used for transparent soap, textile soap, typewriter-inks, perfume, aromatics, varnishes and paints.
The seed cake is used as a fertilizer. The writing and printing-papers are made of the wood-pulp. Castor stems are used for strawboards and cheap wrappings.
35. Tragia involucrate; (Verna-Barhaita)-The roots and fruits are used medicinally.
Systematic Relationships:
Bentham and Hooker have included nine families in the series Unisexuales. They are Euphorbiaceae, Balanopseae, Urticaceae, Plantanaceae, Leitnerieae, Juglandeae, Myricaceae, Casuarineae and Cupuliferae.
Hallier included the family Euphorbiaceae in his Passionales, Rendle and Hutchinson placed the family in the order Euphorbiales.