The scientific classification of Old Man Cactus and Calla Lily 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 Calla Lily kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Old Man Cactus and Calla Lily family is a major factor of Old Man Cactus and Calla Lily 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 Calla Lily belongs to the family Araceae.
While comparing scientific classification, Old Man Cactus and Calla Lily genus and other classification are also important. Also, when you compare Old Man Cactus and Calla Lily, 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 Zantedeschia. Old Man Cactus tribe is Pachycereeae and Calla Lily tribe is Zantedeschieae. Old Man Cactus clade is Angiosperms, Core eudicots and Eudicots and order is Caryophyllales whereas Calla Lily clade is Angiosperms and Monocots and order is Alismatales. Every plant have subfamilies. Old Man Cactus subfamilies are, Cactoideae and Calla Lily subfamilies are Aroideae. In this way you can compare scientific classification of Old Man Cactus and Calla Lily and other products also.