$A$ plant may have different names in different regions of the world. How do botanists solve this problem?

$Nicotiana \ sylvestris$ flowers only during long days and $N. \ tabacum$ flowers only during short days. If raised in the laboratory under different photoperiods,they can be induced to flower at the same time and can be cross-fertilized to produce self-fertile offspring. What is the best reason for considering $N. \ sylvestris$ and $N. \ tabacum$ to be separate species?

Hutchinson's system of classification was revised in

$A$ system of classification in which a large number of traits are considered is

The scientific name of Sunflower is:

Give a scientific reason: There is a need to standardize the names of living organisms.