The scientific classification of Saguaro and Oleander 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. Saguaro and Oleander kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Saguaro and Oleander family is a major factor of Saguaro and Oleander 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. Saguaro belongs to the family Cactaceae and Oleander belongs to the family Apocynaceae.
While comparing scientific classification, Saguaro and Oleander genus and other classification are also important. Also, when you compare Saguaro and Oleander, other factors should also be taken into considerations like order, subfamilies, tribe, clade etc. First plant's genus is Carnegiea and other plant's genus is Nerium. Saguaro tribe is Pachycereeae and Oleander tribe is Wrightieae. Saguaro clade is Angiosperms, Core eudicots and Eudicots and order is Caryophyllales whereas Oleander clade is Angiosperms, Asterids and Eudicots and order is Gentianales. Every plant have subfamilies. Saguaro subfamilies are, Cactoideae and Oleander subfamilies are Apocynoideae and Hippocastanoideae. In this way you can compare scientific classification of Saguaro and Oleander and other products also.