Both aerial roots and underground roots are adventitious in the plant

In the plant Monstera initial adventitious roots are aerial and later adventitious roots may grow into the soil and as a result adventitious roots are aerial as well as underground in this plant. Mustard has only tap root system which is underground. Wheat has underground fibrous roots. Banyan tree has underground tap root system and later aerial adventitious roots are developed that ultimately enter into the soil to provide pillar like mechanical strength.