11th Class Biology Families Leguminosae or Fabaceae

Leguminosae or Fabaceae

Category : 11th Class

Systematic position

Division      :         Angiospermae

        Class            :         Dicotyledonae

        Subclass     :         Polypetalae

        Series          :         Calyciflorae

        Order          :         Rosales

        Family         :         Leguminosae

Habit : Annual or biennial, herb, shrub or tree.

Root : Tap root system.

Stem : Erect or creeping, solid or weak.

Leaf : Alternate or whorled, stipulate, petiolate, simple or usually compound, reticulate venation.

On the basis of inflorescence and flower characters, this family is divided in to 3 subfamilies :


Subfamily - Papilionatae (Papilionaceae)

Inflorescence : Racemose or solitary axillary.

Flower : Bracteate or ebracteate rarely bracteolate (e.g., Arachis), pedicellate, complete, irregular, zygomorphic, hypogynous, pentamerous.

Calyx : Sepals 5, gamosepalous, usually campanulate, lobes unequal, rarely tubular (e.g., Cyamopsis), odd sepal anterior, may be persistent, inferior.

Corolla : Petals 5, polypetalous, papilionaceous, descending imbricate aestivation, one posterior long standard, two lateral short wings, two anterior petals jointed to each other forming keel.

Androecium : Stamens 10, usually diadelphous (9+1 in Lathyrus, 5+5 in Aeschynomene) or monadelphous (9 in Dalbergia, 10 in Arachis and Erythrina indica), rarely free (e.g., Sophora), nectar gland often present on the inner bases of filaments, anther lobes bilocular, dorsifixed, introrse.

Gynoecium : Monocarpellary, ovary superior, unilocular with marginal placentation ovary covered by staminal tube, style bent, stigma simple or capitate.

Fruit : Legume or lomentum.

Floral formula :


Subfamily – Caesalpinoideae (Caesalpiniaceae)


Inflorescence : Raceme, umbel or a solitary flower.

Flower : Bracteate or ebracteate, pedicellate, hermaphrodite, complete, zygomorphic, hypogynous.

Calyx : Sepals 5, polysepalous, imbricate aestivation.

Corolla : Petals 5, polypetalous, ascending imbricate aestivation.

Androecium : 10 stamens, or staminodes are found as in Cassia, free filaments of unequal size, anther lobes bilocular, introrse, versatile.

Gynoecium : Monocarpellary, unilocular, ovary superior, marginal placentation, stigma capitate.

Fruit : Legume.

Floral formula : or



Subfamily – Mimosoideae (Mimosaceae)

Inflorescence : Head or capitulum or spike, flowers arranged in acropetal succession.

Flower : Bracteate or ebracteate, sessile, hermaphrodite, complete actinomorphic, hypogynous, pentamerous.

Calyx : 5 sepals (4 in Mimosa) gamosepalous, connate at the base, valvate aestivation, rarely imbricate (e.g., Parkia).

Corolla : 5 petals (4 in Mimosa) gamopetalous or polypetalous, membranous, valvate aestivation.

Androecium : In most of the members, stamens are indefinite and polyandrous. However, there are only 4 stamens in Mimosa pudica and 10 each in Prosopis and Dichrostachys. Filaments are long, usually connate at the base, sometimes they are coloured and gland dotted. Anthers are dithecous and introrse.

Gynoecium : Monocarpellary, unilocular, ovary superior, style long, cylindrical, stigma single and capitate, marginal placentation.

Fruit : Lomentum.

Floral formula :



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