 The blue color of L. indigo is due to ( 7 @-@ isopropenyl @-@ 4 @-@ methylazulen @-@ 1 @-@ yl ) methyl stearate , an organic derivative of azulene . It is unique to this species , but similar to a compound found in L. deliciosus . 
 The blue color of L. indigo <a href='drop_aux' title='1'><mark>is</mark></a>due to ( 7 @-@ isopropenyl @-@ 4 @-@ methylazulen @-@ 1 @-@ yl ) methyl stearate , an organic derivative of azulene . It <a href='drop_aux' title='2'><mark>is</mark></a>unique to this species , but similar to a compound found in L. deliciosus . 
Da blue color of L. indigo due to ( 7 @-@ isopropenyl @-@ 4 @-@ methylazulen @-@ 1 @-@ yl ) methyl stearate , an organic derivative of azulene . It unique to this species , but similar to a compound found in L. deliciosus .