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