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