Habit:
Twining climber
Root:
Branched tap root system having nodules.
Stem:
Aerial, weak stem and a twiner
Leaf:
imparipinnately compound, alternate, stipulate showing reticulate venation. Leaflets are stipellate. Petiolate and stipels are pulvinated.
Inflorescence:
Solitary and axillary 
Flower:
Bracteate, bracteolate, bracteoles usually large, pedicellate, heterochlamydeous, complete, bisexual, pentamerous, zygomorphic and hypogynous
Calyx:
Sepals 5, synsepalous, green showing valvate aestivation. Odd sepal is anterior in position.
Corolla:
Petals 5, white .or blue  apopetalous, irregular papilionaceous corolla showing, descendingly imbricate aestivation.
Androecium:
Stamens 10, diadelphous (9)+ 1 nine stamens fused to form a bundle and the. tenth stamen is free. Anthers are dithecous, basifixed, introrse and dehiscing by longitudinal slits.
Gynoecium:
Monocarpellary, unilocular, with many ovules on marginal placentation, ovary superior, style simple and in curved with feathery stigma.
Fruit:
Legume
Seed:
Non-endospermous, reniform.
Floral Formula:

(i) Molecular Taxonomy is the branch of phylogeny that analyses hereditary molecular differences, mainly in DNA sequences, to gain information and to establish genetic relationship between the members of different taxonomic categories.
(ii) The advent of DNA cloning and sequencing methods have contributed immensely to the development of molecular taxonomy and population genetics over the years.
(iii) These modem methods have revolutionised the field of molecular taxonomy and population genetics with improved analytical power and precision.
(iv) The results of a molecular phylogenetic analysis are expressed in the form of a tree called phylogenetic tree.
(v) Different molecular markers like allozymes, mitochondrial DNA, microsatellites, RFLP (Restriction Fragment Length Polymorphism), RAPD (Random amplified polymorphic DNA); AFLPs (Amplified Fragment Length Polymorphism), single nucleotide polymorphism-SNP, microchips or arrays are used in analysis.
Uses of molecular taxonomy:
(i) Molecular taxonomy helps in establishing the relationship of different plant groups at DNA level.
(ii) It unlocks the treasure chest of information on evolutionary history of organisms.

1. Botanists use binomial nomenclature to solve this problem.
2. A scientific name is given to the plant based on certain principles and criteria. 
3. The scientific name of a particular plant is same all over the world and is not given to any other plant.

A widely followed natural system of classification considered the best was proposed by two English botanist George Bentham (1800 - 1884) and Joseph Dalton Hooker (1817-1911).
They described 202 families and 7569 genera and 97, 205 species. In this system the seeded plants were classified into 3 major classes such as Dicotyledonae, Gymnospermae and Monocotyledonae.
Class I Dicotyledonae:
Plants contain two cotyledons in their seed, leaves with reticulate venation, tap root system and tetramerous or pentamerous flowers come under this class. It includes three sub-classes - Polypetalae, Gamopetalae and Monochlamydeae
Sub-class 1. Polypetalae: 
Free petals and dichlamydeous flowers. It is further divided into three series - Thalamiflorae, Disciflorae and Calyciflorae.
Series (i) Thalamiflorae: 
Flowers with dome or conical shaped thalamus and superior ovary. It includes 6 orders and 34 families. 
Series (ii) Disciflorae:
Prominent disc shaped thalamus with superior ovary It includes 4 orders and 23 families.
Series (iii) Calyciflorae:
Flowers with cup shaped thalamus and with inferior or sometimes with half-inferior ovary. Calyciflorae  includes 5 orders and 27 families
Sub-class 2. Gamopetalae: 
United petals, which are either partially or completely fused to one another and dichlamydeous. It is further  divided into three series - Inferae, Heteromerae and  Bicarpellatae
Series (i) Inferae: 
The flowers are epigynous and with inferior ovary. Inferae includes 3 orders and 9 families. 
Series (ii) Heteromerae: 
The flowers are hypogynous, superior ovary and with more than two carpels. Heteromerae includes 3  orders and 12 families. 
Series (iii) Bicarpellatae:
The flowers are hypogynous, superior ovary and with two carpels. Bicarpellatae includes 4 orders and 24 families.
Sub-class 3. Monochlamydeae:
Incomplete flowers either apetalous or with undifferentiated calyx and corolla are placed under Monochlamydeae. The sepals and petals are not distinguished and they are called perianth. Sometimes both the whorls are absent. Monochlamydeae includes 8 series and 36 families.
Class II Gymnospermae:
Plants that contain naked seeds come under this class. Gymnospermae includes three families - Gnetaceae, Coniferae and Cycadaceae.
Class III Monocotyledonae:
Plants contain only one cotyledon in their seed, leaves with parallel venation, fibrous root system and trimerous flowers come under this class. The Monocotyledonae has 7 series and 34 families.
Merits:
(i) Description of plants is quite accurate and reliable because it is mainly based on personal studies from actual specimens and not mere comparisons of known facts.
(ii) As it is easy to follow, it is used as a key for the identification of plants in several herbaria of the world. Though it is a natural system, this system was not intended to be phylogenetic.