According to Ernest Mayr 1963," these are groups of populations that interbreed and are reproductively isolated from other such groups in nature".

Represent diagrammatically
1. Monophyletic group: Taxa comprising all the descendants of a common ancestor.

2. Paraphyletic group: Taxon that includes an ancestor but not all of the descendants of that ancestor.

3. Polyphyletic group: Taxa that includes members from two different lineages

The aims of biosystematics are as follows:
1. To delimit the naturally occurring biotic community of plant species.
2. To establish the evolution of a group of taxa by understanding the evolutionary and phylogenetic trends.
3. To involve any type of data gathering based on modern concepts and not only on morphology and anatomy.

(i) It is a method to identify genetic markers using a randomly synthesized primer that will anneal (recombine (DNA) in the double stranded form) to complementary regions located in various locations of isolated DNA. If another complementary site is present on the opposing DNA strand at a distance that is not too great then the reaction will amplify this region of DNA.
(ii) RAPDs (Random Amplified Polymorphic DNA) like microsatellites may often be used for genetic studies within species but may also be successfully employed in phylogenetic studies to address relationships within a species or between closely related species.

Arachis hypogea (Ground nut) and Pongamia pinnata (Pungam).

1. Plants with free petals and dichlamydeous flowers come under polypetalae. It is further divided
2. into three series - Thalamiflorae, Disciflorae and Calyciflorae.

1. Vernacular names are known as common names.
2. They are very often descriptive and poetic references to plants. Common name refer to more than one plant or many plants may have same common name.
3. These names are regional or local and are not universal. Example: Albizia amara. L belongs to Mimosaceae is called as Usilai in South Tamilnadu and Thurinji in North Tamilnadu.

Anamorph - Asexual reproductive stage of fungus.
Telomorph - Sexual reproductive stage of fungus.

1. When the individuals are similar to one another in one or more features and different
2. from other such groups, they are called morphological species . 
3. These species are defined and categorized with no knowledge of phylogenetic history, gene flow or detailed reproductive mechanisms.

1. Division is the next level of classification that consists of number of classes.
 Example: Magnoliophyta.
2. Kingdom is the highest level or rank of the classification. Example: Plantae.

1. Order includes group of families which show less similarities among them.
2. Class consists of group of orders which share few similarities.