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Family: Fabaceae, Sub-family: Papilionoideae (Legume family)

Distribution: cosmopolitan in distribution, except in artic region. This sub-family consist of 425 genera and 12,150 species

Habitat: terrestrial, wild or cultivate for pulses and oil

Habit: annual or perennial herbs, climbers (Lathyrus), shrubs (Sesbania), or trees (Dalbergia)

Root: tap root with nodulated, root nodules consisting of symbiotically associated nitrogen fixing bacteria Rhizobium

Stem: aerial, erect, climbers supported by tendrils (Pisum), branched, cylindrical or quadriangular (Vicia faba), herbaceous or woody (Darbergia), solid or fistular (Vicia faba), glabrous or pubescent

Leaf: cauline and ramal, alternate or opposite or whorl, stipulate (foliaceous stipule), Petiolate, pulvinous petiole (Glycine max), simple (Crotolaria), pinnately or palmately compound lead, terminal leaflets are modified into tendrils (Pisum) or rudimentary (Vicia faba), entire, mucronate, pubescent or glabrous, unicoasted reticulate venation

Inflorescence: racemose, raceme (Pisum), panicle (Darbergia), solitary axillary (Lathyrus), head (Trifolium)

Flower: bracteate, pedicellate, zygomorphic, complete, bisexual, pentamerous, hypogynous, papilionaceous, variously colour

Calyx: sepals five, gamosepalous, odd-anterior, ascending imbricate aestivation, campanulate, persistent, sepaloid, inferior

Corolla: petals five, two gamopetalous, three polypetalous, posterior larger petals known as vexillium or standard, lateral middle medium petals known as wing or alae and anterior two small fused petals known as keel or carina, papilionaceous, vexillary aestivation, variously color, inferior

Androecium: stamens ten, diadelphous, one polyandrous, nine synandrous, filaments of nine stamens fused together to form a staminal tube that encloses style and stigma, Monadelphous (Crotalaria), anther dithecous, dorsifixed or basifixed, introrse, inferior

Gynoecium: carpel one, monocarpellary, ovary superior, unilocular with many ovules, marginal placentation, style short and bent, stigma capitate

Fruit: simple, dry, dehiscent, legume or pod or lomentum

Seed: two cotyledons, mainly albuminous

Floral formula with diagram:


Identifying characters

Nodulated roots, nodules cosisting of symbiotically associated Rhizobium bacteria

Foliaceous stipule

Papilonaceous flower

Odd anterior sepals, ascending imbricate aestivation, persistent calyx

Presence of standard or vexillium, wing or aleae, keel or carina, vexillary aestivation

Diadelphous stamens, presence of staminal tube that encloses style and stigma

Unilocular with many ovules, marginal placentation

Legume or lomentum or pod



Kingdom: Plantae

Division: Phanerogams

Sub-division: Angiospermae

Class: Dicotyledonae

Sub-class: Polypetalae

Series: Calciflorae

Order: Rosales

Family: Fabaceae

Sub-family: Papilionoideae


Economically important plants

Dalbergia sissoo

Pisum sativum

Lathyrus orodatus

Glycine max

Cajanus cajan

Phaseolus mungo

Lens esculentum

Trifolium repens

Arachis hypogaea  

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