Systematic botany is the science that deals with classification of plant into groups based on certain key characters, this process includes their evolutionary relationships and nomenclatures.
Classification of organisms into various kingdoms have been done by systematics.
Then, the main goal of systematics is the systematic arrangement of organisms based on their characteristics, similarities, and the relationships between them.
The main difference between taxonomy and systematics is that taxonomy is involved in the classification and naming of organisms whereas systematics is involved in the determination of evolutionary relationships of organisms.