It is worth spending some time considering what a character is, and what it is not. Scientists do tend to use it in different ways. If you are aware of the different meanings that it may have, you will find it easier to determine how a particular author is using it. A character is a feature that can be measured, counted, described, or otherwise expressed. It is an abstract entity.
Petal color is a character.
Plant height is a character. Position 33 from the end of a gene is a character. Characters have states . In taxonomy, some characters are more equal than other characters, but which characters these are varies from group to group. First of all, one needs to decide if a character is a good taxonomic character for the plants that one is studying.