The scientific classification of Old Man Cactus and American Agave 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. Old Man Cactus and American Agave kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Old Man Cactus and American Agave family is a major factor of Old Man Cactus and American Agave 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. Old Man Cactus belongs to the family Cactaceae and American Agave belongs to the family Agavaceae.
While comparing scientific classification, Old Man Cactus and American Agave genus and other classification are also important. Also, when you compare Old Man Cactus and American Agave, other factors should also be taken into considerations like order, subfamilies, tribe, clade etc. First plant's genus is Cephalocereus and other plant's genus is Agave. Old Man Cactus tribe is Pachycereeae and American Agave tribe is Not Available. Old Man Cactus clade is Angiosperms, Core eudicots and Eudicots and order is Caryophyllales whereas American Agave clade is Angiosperms and Monocots and order is Asparagales. Every plant have subfamilies. Old Man Cactus subfamilies are, Cactoideae and American Agave subfamilies are Agavoideae. In this way you can compare scientific classification of Old Man Cactus and American Agave and other products also.