Leguminosae
| Home | | Pharmacognosy |Chapter: Pharmacognosy and Phytochemistry : Study of Different Families
A British systematic botanist J. Hutchinson published his work, The Families of Flowering Plants in 1926 on dicotyle-dons and in 1934 on monocotyledons. Hutchinson made it clear that the plants with sepals and petals are more primitive than the plants without petals and sepals on the assumption that free parts are more primitive than fused ones.
LEGUMINOSAE
Habit: These are herbs, shrubs, trees, twiners or climb-ers.
Roots: The roots of many species, particularly of
Pap-ilionaceae, have tubercles.
Leaves: These are alternate, pirnnately compound, and rarely
simple, as in rattlewort (Crotalaria
sericea), camel’s foot tree (bauhinid) and some species of desmodium, e.g. D. gangeticum, with a swollen leaf-base known as the pulvinus. There
are two, usually free, stipules.
Flowers: These are bisexual and complete, regular or
zygomorphic or irregular, and hypogynous or slightly perigynous.
Calyx: There are usually 5 or (5) sepals, with the odd one
anterior (away from the axis). Sometimes there are four sepals. They may be
united or free.
Corolla: There are usually five petals, with the odd one
posterior (towards the axis). Sometimes there are four petals, free or united.
Androecium: There are usually 10 or more stamens (often less
than 10 by reduction) free or united.
Gynoecium: There is one carpel. The ovary is one-celled,
with one to many ovules. It is superior and the placentation is marginal. The
ovary often borne on a long or short stalk is called the stipe or gynophore.
Fruit: This is mostly a legume or pod (dehiscent), or
sometimes a lomentum (indehiscent).
This is the second biggest family among the dicotyledons,
and has varying characteristics. As such, it has been divided into the
following sub-families: papilionaceae,
caesalpin-ieae and mimoseae. The division is primarily based on the
characteristics of the corolla and the stamens.
Papilionaceae
Habit: Herbs, shrubs, trees and climbers.
Leaves: Unipinnate, sometimes trifoliate, rarely simple;
stipels often present.
Inflorescence: Usually a raceme.
Flowers: Zygomorphic, polypetalous and papiliona-ceous.
Calyx: Usually has five sepals, gamosepalous, often
imbricate, sometimes valvate.
Corolla: Usually has five petals, free, of very unequal
sizes, the posterior and largest one being the vexillum or standard, the two
lateral ones being the wings or alae, and the two innermost ones (apparently
united) forming the keel or carina; aestivation vexillary.
Androecium: Stamens 10, diadelphous (9) + 1, rarely 10,
free, as in coral tree (erythrina),
or (10), connate, as in rattlewort (crotalaria).
Floral formula: ·׀·H K(5) C5 A(9) + 1 G1
Examples: Methi, indigo, bengal gram, etc.
Caesalpinieae
Habit: Shrubs trees, rarely climbers or herbs.
Leaves: Unipinnate or bipinnate, rarely simple, as in
camel’s foot tree (Bauhinia); stipels
absent.
Inflorescence: Mostly a raceme.
Flowers: Zygomorphic or irregular and polypetalous.
Calyx: Sepals usually have five, polysepalous (sometimes
gamosepalous), imbricate.
Corolla: Usually have five petals, free, subequal or
unequal, the odd or posterior one (sometimes very small) always innermost;
aestivation imbricate.
Androecium: There are 10 stamens, or less by reduction;
free.
Floral formula: ·׀·H K5 C5 A10 G1
Examples: Indian Senna, Saraca indica, etc.
Mimoseae
Habit: Shrubs and trees, sometimes herbs or woody climbers.
Leaves: Bipinnate; stipels present or absent.
Inflorescence: A head or a spike.
Flowers: Regular, often small and aggregated in spheri-cal
heads.
Calyx: (5) or (4) sepals, generally gamosepalous, valvate.
Corolla: (5) or 4) petals, mostly gamopetalous; aestiva-tion
valvate.
Androecium: Usually ∞ stamens, sometimes 10 (as in Entada, Neptunia, Prosopis and Parkia), free, often united at the base; pollen often united in
small masses.
Floral formula: ⊕ H K(5 – 4) C(5 – 4) A ∞ or 10 G1
Examples: Catechu and other species of acacia, Mimosa pudica, etc.
Floral diagram of mimoseae
