The scientific classification of Petunia and Echinocactus includes the entire classification chart that includes kingdom, family, clade, tribe etc. A kingdom is the second highest taxonomic rank. A taxonomic rank is the level that a living organisms are placed in hierarchical level of arrangement of life forms. All the living organisms are divided into kingdoms. Plant kingdom is a main classification of living organisms that include all plants. There are six kingdoms which are: Plantae, Animalia, Fungi, Protista, Aschaea/Archaeabacteria and Bacteria Eubacteria. Petunia and Echinocactus kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Petunia and Echinocactus family is a major factor of Petunia and Echinocactus Scientific Classification. Plant family helps you narrow the search of your plants. It also gives you idea about, how the plant looks, how the seed will be like etc. These two plant families can be different or same. Petunia belongs to the family Solanaceae and Echinocactus belongs to the family Cactaceae.
While comparing scientific classification, Petunia and Echinocactus genus and other classification are also important. Also, when you compare Petunia and Echinocactus, other factors should also be taken into considerations like order, subfamilies, tribe, clade etc. First plant's genus is Petunia and other plant's genus is Echinocactus. Petunia tribe is Not Available and Echinocactus tribe is Cacteae. Petunia clade is Angiosperms, Asterids and Eudicots and order is Solanales whereas Echinocactus clade is Angiosperms, Core eudicots and Eudicots and order is Caryophyllales. Every plant have subfamilies. Petunia subfamilies are, Petunioideae and Echinocactus subfamilies are Cactoideae. In this way you can compare scientific classification of Petunia and Echinocactus and other products also.