The scientific classification of Rhubarb and Siberian Iris 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. Rhubarb and Siberian Iris kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Rhubarb and Siberian Iris family is a major factor of Rhubarb and Siberian Iris 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. Rhubarb belongs to the family Polygonaceae and Siberian Iris belongs to the family Iridaceae.
While comparing scientific classification, Rhubarb and Siberian Iris genus and other classification are also important. Also, when you compare Rhubarb and Siberian Iris, other factors should also be taken into considerations like order, subfamilies, tribe, clade etc. First plant's genus is Rheum and other plant's genus is Iris. Rhubarb tribe is Not Available and Siberian Iris tribe is Irideae. Rhubarb clade is Angiosperms, Core eudicots and Eudicots and order is Caryophyllales whereas Siberian Iris clade is Angiosperms and Monocots and order is Liliales. Every plant have subfamilies. Rhubarb subfamilies are, Not Available and Siberian Iris subfamilies are Iridoideae. In this way you can compare scientific classification of Rhubarb and Siberian Iris and other products also.