In this article we will discuss about:- 1. Distribution of Fabaceae-Papilionaceae 2. Vegetative Characters of Fabaceae-Papilionaceae 3. Economic Importance 4. Important Types.
Distribution of Fabaceae-Papilionaceae:
The family is also known as Fabaceae. It includes 600 genera and 1200 spices. It is regarded as the second largest family of dicotyledons. In India the family is represented by 1100 species and 100 genea. The family divided into 3 sub-families based upon the floral characters.
The 3 sub-families are considered as 3 separate families e.g. Papilionaceae, Caesalpiniaceae and Mimosaceae by many botanists. Senn (1943) on the basis of comparative wood anatomy suggests that there is not much reason and sharp differences between these sub-families to separate them.
The family Leguminosae is divided into 3 sub-families as:
Sub-family 1. Papilionaceae or papilionoideae:
Flowers medianly zygomorphic; calyx gamosepalous, imbricate; corolla papilionaceous, vexillary; stamens 10, diadelphous or monadelphous.
Sub-family 2. Caesalpinioideae:
Flowers slightly irregular; calyx free or united, corolla free, imbricate; stamens 10 or few, free.
Sub-family 3. Mimosoideae:
Flowers actinomorphic; sepals and petals valvate; free or united, stamens 4 to many.
Papilionaceae:
Diagnostic features:
Herbs, shrubs or trees, generally climbers; leaves alternate, stipulate, simple or compound; flower zygomorphic, hermaphrodite, corolla papilionaceous, stamens 10 or 9 diadelphous or monadelphous; carpel one, fruit legume.
Distribution of Fabaceae-Papilionaceae:
It is commonly called pea family. It includes 375 genera. The family is represented in India by 70 genera and 754 species. The members of this family are xerophytes, mesophytes, hydrophytes and halophytes (Desmodium lattifolium).
Characters of Fabaceae-Papilionaceae:
A. Vegetative Characters:
Habit:
The plants show great variation in habit. The plants may be herbs (Melilotus, Medicago, Trifolium), shrub, (Butea, Flemingia), climbers (Lathyrus, Pisum, Vicia), twinners (.Dolichos, Vigna) and trees (Dalbergia, Sesbania, Erythrina). Aeschynomene is an aquatic plant-
Root:
A much branched tap root system, bearing bacterial nodules.
Stem:
Herbaceous or woody, erect or twinner, branched, angular or cylindrical, solid or fistular.
Leaves:
Cauline or ramal; alternate, stipulate, compound mostly trifoliate sometimes simple as in Alysicarpus; modified partly or wholly into tendril (Lathyrus, Pisum, Vicia) leaf base may be pulvinate. In Lathyrus aphaca the entire leaf becomes modified into a tendril; in Pisum and Lathyrus the stipules are foliaceous and highly developed, in Pisum and Vicia the leaflets are modified into tendrils.
In Lupinus and Medicago stipules are adnate. In Desmodium gyrans the two lateral leaflets perform autonomous movements. Sir J.C. Bose had done much work on the physiology of leaf movement in this species.
B. Floral characters:
Inflorescence:
Racemose raceme, rarely solitary axillary.
Flowers:
Medianly zygomorphic, hermaphrodite, pedicellate, slightly perigynous, complete and pentamerous. The papilionaceous corolla is typical. The floral characters are rather uniform.
Calyx:
Sepals 5, gamosepalous odd sepal anterior, sepaloid, ascending imbricate aestivation.
Corolla:
Petals 5, polypetalous, papilionaceous, posterior petal outermost large – the vexillium or standard; next two lateral ones-the wings or alae; and the two anterior and innermost united to form a boat-shaped structure – the keel or carina; descending imbricate or vexillary aestivation.
Androecium:
Stamens 10 or rarely nine (Abrus, Dalbergia), diadelphous or monadelphous (Crotalaria), posterior stamen is free and filaments of nine are fused to form a sheath around the ovary; in Arachis ten stamens are monadelphous and in Sophora all ten stamens are free.
Gynoecium:
Monocarpellary; ovary superior, unilocular, marginal placentation, numerous ovules on the ventral suture; style long slightly bent at the apex, flattened, hairy or without hair (Mucuna): stigma simple or capitate (Mucana).
Fruit:
Legume or pod, indehiscent (Dalbergia), lomentum (Alysicarpus).
Seed:
Non-endospermic.
Pollination:
Entomophilous.
Floral formula:
Pollination mechanism in the Papilionaceae:
The members of Papilionaceae are all pollinated by bees and though they vary greatly in structure yet in the following points all are similar:
1. The flowers more or less horizontal and stigma and anthers are so exposed so as to contact the ventral part of the bee.
2. The two petals fuse and form the “keel” protecting the stamens and carpel from rain.
3. The two ‘wings’ serve as a platform for the bees and also serve as a lever for depressing the carina.
4. The standard serves to make the flower conspicuous.
5. Since the reproductive organs have to come in contact with the ventral side of the bee, it is evident that access to honey should be arranged in such a way that the bees have to pass above the reproductive organs. Accordingly the fused filaments have a passage on their upper sides and the single stamen becomes separate from the rest.
In the manner in which pollen is applied to the bee four different types of structures are met with:
1. In Melilotus, Trifolium etc., the stamens and stigma emerge from the carina and later return back to it thus admitting repeated insect visits.
2. In Medicago, Genista etc., the essential organs remain in a state of tension. As soon as an insect visit, the flower, they explode violently.
3. In Lupinus etc., a piston like mechanism squeezes pollen grains from the apex of the carina and thus permits numerous visits by insects.
4. In Pisum, Vicia, Lathyrus, Phaseolus etc., the style has a brush of hairs which sweeps the pollen in small portions out of the apex of the keel. Repeated insect visits are fruitful in these cases.
Economic Importance of Fabaceae-Papilionaceae:
1. Food:
The fruits and seeds of Pisum sativum (H. Matar), Cicer arietinum, (H. Chana), Cajanus cajan (H. Arhar), Dolichos lablab (H. Sem), Vigna aconitifolius (H. Moth), Phaseolus radiatus (H. Moong), P. mungo (H. Urd), Lens esculenta (H. Masur), Glycine max (Soyabean) are used as vegetable and pulse. Soya-bean is supposed to contain very high percentage of proteins comparable to meat.
2. Oil:
The seeds of Arachis hypogea are pressed to obtain an oil. It is converted into vegetable ghee after hydrogenation and largely used as substitute for pure ghee. The oil cake is used for cattle feeding. Mungfali is also eaten after roasting.
3. Medicine:
Glycyrrhiza glabra (H. Mulathi) is used in throat pain and cough. Physostigma venenosum has several alkaloids and sometimes used as an eye ointment. The fresh juice of the leaves of Abrus precatorius (H. Ratti) is said to remove spots of leucoderma. Its seeds have constant weight to an astonishing degree and traditionally used by goldsmiths.
Cyamopsis tetragonoloba (syn. Psoralea tetragonolaea) seeds are laxative, stimulant and produce a colourless essential oil. The juice of Sesbania grandiflora flowers is said to improve eye sight.
4. Fibre:
Crotalaria juncea (Sunn Hemp or H-Swun) yields fibres, which are used for making rope, mat, coarse canvas, sacks, nets etc. It is a blast fibre.
5. Timber:
Dalbergia sissoo (H. Shismam), D. latifalia (Indian rose wood) yield timber.
6. Dye:
Indigofera tinctoria yields a dye – the indigo (H. Neel).
7. Ornamental and miscellaneous:
Many plants viz., Lathyrus odoratus, Clitoria, Sesbania, Lupinus, Genista, Robinia, etc. are used as ornamental plants in gardens.
Erythrina – (Indian Coral tree) is bird pollinated and produces beautiful red flowers.
Peru balsam and Tolu balsam are obtained from Mysoxylon. Gum tragacinth is obtained from Astragalus gummifer. Gum is also obtained from Butea monosperma and Pterocarpus. Because of root nodules many plants of this family can enrich the soil with fixed nitrogen. Hence they are often used in crop rotation.
Primitive characters:
1. Leaves alternate, stipulate and simple in some species (Indigofera cordifolia, Heylandia).
2. Flowers hermaphrodite, large and showy.
3. Corolla polypetalous.
4. Androecium polyandrous in Ormosia, Baphia, Sophora.
5. Ovules anatropus.
Advanced characters:
1. Plants herbaceous, annual.
2. Leaves compound and in many genera leaflets are modified into tendrils (Pisum, Lathyrus)
3. Flowers zygomorphic.
4. Calyx gamosepalous.
5. Corolla papilionaceous.
6. Stamens diadelphous.
7. Gynoecium monocarpellary.
8. Fruit simple legume.
9. Ovules campylotropous.
10. Seeds non-endospermic.
Important Types of Fabaceae-Papilionaceae:
1. Lathyrus odoratus (Fig. 52.1):
Habit:
A cultivated, climbing herb.
Root:
Tap, branched.
Stem:
Herbaceous, weak, fistular, branched, hairy.
Leaf:
Alternate, petiolate, stipulate, stipules leafy, pinnately compound, imparipinnate, upper leaflets are modified into tendrils and help in climbing.
Leaflets:
Opposite, ovate-elliptical, wavy margin, acute apex unicostate, reticulate venation.
Inflorescence:
Racemose or solitary axillary.
Flower:
Bracteate, pedicellate, complete, hermaphrodite, zygomorphic pentamerous, hypogynous.
Calyx:
Sepals 5, gamosepalous, pentapartite, companulate, odd sepal anterior, imbricate aestivation, green, hairy.
Corolla:
Petals 5, polypetalous, papilionaceous, consisting of a large posterior petal – the vexillum or standard, two lateral-alae or wings and two inner fused to form a boat shaped structure the keel or carnia, vexillary aestivation.
Androecium:
Stamens 10, diadelphous, nine are fused by the lower halves of their filaments to form a tube round the ovary and tenth posterior one free, anthers basifixed, introrse, dithecous, enclosed in the keel.
Gynoecium:
Monocarpellary, ovary superior, unilocular, hairy, elongated, laterally compressed, marginal placentation ovules many, style long, stigma hairy.
Floral formula:
2. Pisum sativum:
Habit:
An annual herb.
Root:
Tap, branched contain nodules.
Stem:
Herbaceous, weak, cylindrical, branched, hairy, climber.
Leaf:
Alternate, petiolate, stipulate, stipules foliaceous, pinnately compound, 2-6 leaflets, terminal leaflets modified into tendrils, leaflets entire, acute.
Inflorescence:
Typical raceme.
Flower:
Bracteate, pedicellate, complete, zygomorphic, hermaphrodite, hypogynous.
Calyx:
Sepals 5, gamosepalous, valvate aestivation.
Corolla:
Petals 5, polypetalous, papilionaceous, standard, wings and keel, descending imbricate aestivation.
Androecium:
Stamens 10, diadelphous, 9 fused in a single bundle, one free, anthers basifixed, dithecous, introrse.
Gynoecium:
Monocarpellary, ovary superior, unilocular, marginal placentation, style one inflexed.
Floral formula:
3. Crotalaria medicaginea Lamk. (Fig. 52.2):
Habit:
Annual herb.
Root:
Tap.
Stem:
Herbaceous, aerial, erect, cylindrical, solid branched, hairy and green.
Leaf:
Cauline and ramal, alternate, stipulate, stipules free-lateral, petiolate, compound trifoliate, pulvinate, leaflets oblong-obovate, entire, emarginate, unicostate reticulate.
Inflorescence:
Raceme.
Flower:
Bracteate, pedicellate, complete, hermaphrodite, zygomorphic, pentamerous, perigynous and cyclic.
Calyx:
5 sepals, gamosepalous, valvate, green, odd sepal anterior.
Corolla:
5-petals, polypetalous, papilionaceous, descending imbricate (vexillary) aestivation, standard, wings and keel; yellowish in colour.
Androecium:
10-stamens, monadelphous (all the filaments are fused to form a staminal tube in the genus) dithecous, dorsifixed and introrse.
Gynoecium:
Monocarpellary, slightly semi-inferior, unilocular, marginal placentation, style curved, capitate stigma.
Fruit:
Legume.
Floral formula:
Common plants of the family:
1. Abrus precatorius (H. Ratti):
The seeds of this plant are used by goldsmiths as small weights called “ratti”.
2. Butea monosperma (Syn. B. frondosa):
It is called Flame of the Forest or parrot tree. The flowers are sold in the market by the name of “Tesu”.
3. Desmodium gyrans:
Indian Telegraph plant. It is a plant of waste places and is noted for the autonomous movements.
4. Melilotus indica (H. Ban-methi):
Annual herb with yellow flowers.
5. Pongamia pinnata (Syn. P. glabra; H. Karanja):
It is a tree, planted on avenues.
6. Aeschynomene aspera and A. indica:
These plants are having pith like stem used for making sholar-hats, nets, baskets and rafts.