Common names . Indian ricegrass is an example of a common name. Bluebell' is an example of a common name that means different things to different people. All the species called bluebells have blue, bell-shaped flowers but they are not particularly closely related. Bluebells in England are monocots, what North American horticulturalists call wild hyacinths, but in Scotland and western North America they are dicots, but not the same dicots in the two countries.
Pepper is another common name with multiple meanings.
Ask where the peppers are in a local supermarket and you will be sent to the produce section where you will find bell peppers. These are members of the genus Capsicum and are related to eggplant, potatoes, and deadly nightshade. In Australia and England such peppers are sold in the supermarkets and groceries as capsicum. True pepper, the kind that is found in a pepper grinder, belongs to a different family altogether. The above examples show that common names are not good indicators of taxonomic relationship.