It represents our attempt to make sense of the biological diversity around us. Over the centuries it has been found that certain approaches to achieving this understanding are more productive than others. These approaches require an understanding of biological principles, but they also help us acquire a better understanding of biology. It is in this sense that taxonomy can be considered a science. It is, however, a science in which two individuals faced with the same information may draw different conclusions as to how much variation should be included in the same taxon.
Taxonomists have to accept diversity of opinion as a fact of life.
You must also recognize that no one gave plants a set of instructions as to how they should behave, how they should restrict their reproductive endeavors, and how variable they could be. During the semester, you will become aware that plants are remarkable for their versatility and plasticity. This frequently frustrates the efforts of humans to place them in neat and tidy boxes.