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Fabaceae, the third largest family among angiosperms after the Orchidaceae (orchid family) and the Asteraceae (aster family), has more than 700 generations and some 20,000 species of trees, shrubs, vines, and herbs and they are being distributed around the globe. Fabaceae belongs to a family of angiosperms. It is also known as Leguminosae and the plants are often called legumes. It is widely distributed around the world. Includes many important pulses such as peas, soybeans, peas, etc.
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Keyterms: Flower, Angiosperms, Orchidaceae, Asteraceae, Leguminosae, legumes, peas, soybeans, trees, shrubs, vines, and herbs
Floral formula of Fabaceae
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The floral formula is one way to summarize all aspects of the flower, making use of different letters, numbers, and symbols. The letters used in the flower formula show the members of the perianth and other parts of the flower. The flower formula is a symbolic representation of the different parts of flowers, their numbers, the pattern of arrangement, and how they relate to each other. The flower formula of the Pisum sativum (pea) of the Fabaceae family is as follows:
%![]()
K (5) C1 + 2 + (2) A (9) +1 G1
Here is the meaning of the symbols below,
| % | Zygomorphic (bilateral symmetry) |
| | Bisexual |
| K(5) | Calyx – 5 sepals, gamosepalous (united) |
| C1+2+(2) | Corolla – 5 petals, polypetalous |
| A(9)+1 | Androecium – 10 stamens, diadelphous |
| G1 | Gynoecium – monocarpellary, superior ovary |

Also Read:
| Related Topics | ||
|---|---|---|
| Plumule | Radicle | Androecium |
| Modifications of Root | Modifications of Stem | The Flower |
Systematic Position of Fabaceae
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The following table represents the systematic position of Fabaceae
| Kingdom | Plantae |
|---|---|
| Subkingdom | Tracheobionta |
| Superdivision | Spermatophyta |
| Division | Magnoliophyta |
| Class | Magnoliopsida |
| Sub-class | Rosidea |
| Order | Fabales |
| Family | Fabaceae |
| Origin | Dicotyledons, taproot with root nodules |
| Stem | Straight or vertical; Fabaceae includes shrubs, herbs, trees, and shrubs. |
| Leaves | Petiolate, pinnately compound or simple; the base of the pulvinus leaf, we say; reticulate venation. |
Fabaceae contains 750 genera and 20,000 species. Astragalus, Acacia, Indigofera, Crotalaria and Mimosa are the five major genera of the Fabaceae family. Some common examples are:
| Common name | Scientific name |
|---|---|
| Acacia | Acacia |
| Alfalfa | Medicago sativa |
| Mulethi (Liquorice) | Glycyrrhiza glabra |
| Common bean | Phaseolus vulgaris |
| Pigeon pea (Arhar) | Cajanus cajan |
| Mung bean | Vigna radiata |
| Chickpea | Cicer arietinum |
| Cowpea | Vigna unguiculata |
| Fenugreek | Trigonella foenum-graecum |
| Hyacinth bean (Sem) | Lablab purpureus |
| Indigo (Neel) | Indigofera |
| Touch me not | Mimosa pudica |
| Sunn hemp | Crotalaria juncea |
| Peas | Pisum sativum |
| Peanuts | Arachis hypogaea |
| Soybean | Glycine max |
| Tamarind | Tamarindus indica |
| Broad beans | Vicia faba |
Also, read: Morphology of Flowering plants
Economic Importance of Fabaceae
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- Many plants are a source of edible oils such as peanuts, soybeans, etc.
- Indigo is the most widely used dye we find at Indigofera.
- Many plants provide pulses, e.g. moon, beans, arhar dal, masoor dal, gram, soybeans, sem, etc.
- Some of the plants are used for decorative purposes, e.g. Sesbania, Lupinus, sweet peas, etc.
- Many plants have medicinal properties. Eg. Mulethi is a very effective cough remedy.
- Some plants produce fibers, e.g. Sunn hemp.

Characters of Fabaceae
- They help to increase the amount of nitrogen in the soil and are a rich source of protein for humans and animals.
- For many years, legumes have been used as an attractive plant in the world, often in the construction and maintenance of small gardens to large parks.
- Thus, Fabaceae are well known for their various uses in agriculture, agriculture, medical sector, the industrial sector, etc.
Also, read: Class 11 Biology Chapter 5 Morphology of Flowering Plants
Things to Remember
- The flowers of the Fabaceae family are zygomorphic, bisexual, pentamerous, and hypogynous.
- Corolla has five, polypetalous leaves with vexillary aestivation.
- The Calyx has five sepals, combined or with a gamosepalous with valvate or imbricate aestivation.
- Papilionoideae was the original (previous) name of this family.
- The Fabaceae family is found everywhere except Antarctica and the arctic highlands.
Also Read:
Previous Years Questions
- Which one of the following plants belongs to the Family Apocynaceae?….[COMEDK UGET 2009]
- Madhunashini is the popular name for ............... plant...[COMEDK UGET 2006]
- Indefinite number of stamens are the characteristic of the family….[COMEDK UGET 2007]
- Arrangement of sepals or petals with respect to eachother in the floral bud is called...[COMEDK UGET 2006]
- Apocarpous gynoecium and rattle shaped stigma .are characteristic features of which family?...[COMEDK UGET 2008]
- The phyllotaxy is of decussate type in...[COMEDK UGET 2008]
- The spines in a cactus (Opuntia) are modified form of.......[COMEDK UGET 2010]
- In which of following groups of plants, the life cycle includes the gametophytic phase….[COMEDK UGET 2012]
- Which one of the following families has features like bisexual, pentamerous, gamopetalous….[COMEDK UGET 2012]
- Carrot is a… [BCECE 2010]
- Banana is...[COMEDK UGET 2006]
- The edible part in Orange is….[BHU UET 2012]
- When placenta forms a ridge along the ventral suture of the ovary and...[AMUEEE 2012]
- When margin of thalamus grows upward enclosing ovary completely and….[AMUEEE 2012]
- Leaf tendrils are found in….[AMUEEE 2015]
Sample Questions
Ques. Give two ornamental uses of the Fabaceae family. (2 marks)
Ans. The two ornamental uses of the Fabaceae family are given below-
- For many years, legumes have been used as an attractive plant in the world, often in the construction and maintenance of small gardens to large parks.
- Ornamental trees and shrubs include the golden chain tree, Black locust, Honey locust, acacia, Plant, and Delonix.
Ques. How do the Fabaceae plants maintain nitrogen levels in the agricultural fields? (2 marks)
Ans. Nitrogen (N) is an important component of the building blocks of almost all plant structures as well as an essential component of chlorophyll, enzymes, and proteins. It is used in greater amounts than other plant nutrients. Plants can directly absorb nitrate and ammonium from the soil. However, in the absence of these nitrogen sources, certain plant species of the family Fabaceae (legumes) develop symbiotic relationships with a nitrogen-fixing bacterial group called Rhizobia.
Ques. How do Fabaceae plants reproduce? (2 marks)
Ans. There are usually ten stamens and one ovary with a high, curved style. They are usually arranged in endless inflorescences. Fabaceae are usually entomophilous (i.e., pollinated by insects), and the flowers are often showy to attract pollinators. Unique in the Fabaceae are flowers and fruits. Like most flowers, those found in legume plants are hermaphroditic, which contains both stamen and pistil. This allows the plants to reproduce on their own, which means that each plant can reproduce itself which can have the effect of preventing genetic diversity.
Ques. Why are Fabacaea family plants useful for the farmers? (2 marks)
Ans. The Fabaceae family is economically viable for farmers because of its ability to fix nitrogen. It helps to save money due to the lower cost of buying fertilizer. Legumes are also used by farmers in crop rotation to replenish nitrogen-depleted soils. This extra nitrogen results in more protein seeds and leaves compared to non-legumes and parts. Moreover, the hydraulic lift is a basic feature of a few types of legumes, making it ideal for plant planting.
Ques. Write a short note on Fabaceae. (2 marks)
Ans. The family Fabaceae, also known as legumes, is one of the most important ecological plants. Legumes help increase nitrogen in the soil and provide a rich source of vegetable protein for humans, livestock, and wildlife. The flowers of the legume family are varied but equally sophisticated. Indeed, the 50 million-year-old legume flowers provide the first example of the equivalent flower in the record of flowering plant residues. Most pods have five petals and five sepals, and the sepals are usually attached to at least the ground. The fruits of the legume family are also varied. Usually, one fruit (pod) is produced per flower.
Ques. Where are Fabacaea family plants found in the world? (2 marks)
Ans. Fabaceae is home to many species of plants in the world. Legumes are abundant in the dry, tropical rain forests, but they are also abundant in the desert to tropical rainforests. They are not uncommon in the highlands of the summer rainy season and the beech forests of the southern Southern Hemisphere. Woody legume species usually live in tropical and subtropical regions, but tropical plant species range from tropical to temperate regions. Therefore, many varieties of legumes are available for use in reforestation or reforestation projects around the world.
Ques. Explain the relationship between legumes and rhizobia. (2 marks)
Ans. Legumes and rhizobia have a symbiotic affinity, which benefits legumes but is not necessary for their growth. Legumes appear to receive nitrogen in other ways other than the nodules first, and the release of soil nitrogen, natural or otherwise, may cause the nodular pods to stop contact with rhizobia. Rhizobia is a compound name for bacteria that attack the roots of the legume and fix nitrogen from the atmosphere, and it is found in the legume plant. Many legumes are at risk of infection with rhizobia, when rhizobia are inserted into the legume plant at the roots, it rarely has stems, nodules.
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