One of the challenges when working with plants or animals is making sure that you are working with the same thing someone else is. The problem with common usage is that one name can be applied to a variety of different plants in different areas, or several names can be used for the same plant. Or sometimes both.
The man who first figured out how to solve this problem was Carolus Linnaeus (born today in 1707). In 1735, he came up with a system, taxonomy, that groups organisms in big chunks, then smaller chunks, then smaller yet. Each species has exactly one name that places it exactly within the taxonomic system, indicating both the genus (like Canis for canids, or dog-like animals) and the species (lupus, for a particular canine commonly called a wolf). The scientific name for dogs, Canis familiaris, indicates that it is similar to the wolf, but not the same. (This system is similar to people’s names, where the last name indicates family and the first name indicates the individual in the family.) In general, biologists agree on these names, but there are always a few critters at the edges that are being shuffled around as new information shows up; for instance, there is disagreement over whether bison should be Bos bison or Bison bison. Still, there are few enough disagreements that the confusion can be identified and managed, so the system works even when it is imperfect.