*These are known as yoked key .
*They wont go taxa.
*They give visual presentation of the group.
*The indent key have the two lead of each couplet separated by the couplet following the first lead that
making it difficult to compare with the alternatives .
*There is a wastage of paper because the keys utilize the right side of the paper and so they are expensive to print .
Bracketed key: These are known as parallel keys.
*They will group taxa.
*They don't give a visual presentation of the group.
*The bracketed key keep the two leads of every couplet for and easier comparison of the alternatives .
*The bracketed keys utilize the space in each page efficiently and so they are cheaper to print.