The scientific classification of Saguaro and Citrus 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 Citrus kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Saguaro and Citrus family is a major factor of Saguaro and Citrus 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 Citrus belongs to the family Rutaceae.
While comparing scientific classification, Saguaro and Citrus genus and other classification are also important. Also, when you compare Saguaro and Citrus, 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 Citrus. Saguaro tribe is Pachycereeae and Citrus tribe is Citreae. Saguaro clade is Angiosperms, Core eudicots and Eudicots and order is Caryophyllales whereas Citrus clade is Angiosperms, Eudicots and Rosids and order is Sapindales. Every plant have subfamilies. Saguaro subfamilies are, Cactoideae and Citrus subfamilies are Asteroideae. In this way you can compare scientific classification of Saguaro and Citrus and other products also.