The scientific classification of Rhubarb and Black Walnut 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 Black Walnut kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Rhubarb and Black Walnut family is a major factor of Rhubarb and Black Walnut 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 Black Walnut belongs to the family Juglandaceae.
While comparing scientific classification, Rhubarb and Black Walnut genus and other classification are also important. Also, when you compare Rhubarb and Black Walnut, 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 Juglans. Rhubarb tribe is Not Available and Black Walnut tribe is Juglandeae. Rhubarb clade is Angiosperms, Core eudicots and Eudicots and order is Caryophyllales whereas Black Walnut clade is Angiosperms, Eudicots and Rosids and order is Juglandales. Every plant have subfamilies. Rhubarb subfamilies are, Not Available and Black Walnut subfamilies are Juglandinae. In this way you can compare scientific classification of Rhubarb and Black Walnut and other products also.