What are some limitations of a dichotomous key?

1.It is only useful when the organism that is being identified was or is a part of organisms that are part of the key. An organisms is usually misidentified if it does not belong to the key.  

2.It’s a complex mechanism of organism identification and may leads to chain of worng interpretations.  

3.The characteristics which are devised to identify an organism might not be a distinct feature of the species already exiting in the dichotomous key.

4.Dependency on physical characteristics, does not take into account genetic characteristics

sex cells are usually half's then they find another half and make a fertilize egg