The scientific classification of Tree-of-Heaven and Pearl Millet 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. Tree-of-Heaven and Pearl Millet kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Tree-of-Heaven and Pearl Millet family is a major factor of Tree-of-Heaven and Pearl Millet 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. Tree-of-Heaven belongs to the family Simaroubaceae and Pearl Millet belongs to the family Poaceae.
While comparing scientific classification, Tree-of-Heaven and Pearl Millet genus and other classification are also important. Also, when you compare Tree-of-Heaven and Pearl Millet, other factors should also be taken into considerations like order, subfamilies, tribe, clade etc. First plant's genus is Ailanthus and other plant's genus is Pennisetum. Tree-of-Heaven tribe is Not Available and Pearl Millet tribe is Paniceae. Tree-of-Heaven clade is Angiosperms, Eudicots and Rosids and order is Sapindales whereas Pearl Millet clade is Angiosperms, Commelinids and Monocots and order is Cyperales. Every plant have subfamilies. Tree-of-Heaven subfamilies are, Not Available and Pearl Millet subfamilies are Panicoideae. In this way you can compare scientific classification of Tree-of-Heaven and Pearl Millet and other products also.