The scientific classification of Brugmansia and Crown-of-Thorns 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. Brugmansia and Crown-of-Thorns kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Brugmansia and Crown-of-Thorns family is a major factor of Brugmansia and Crown-of-Thorns 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. Brugmansia belongs to the family Solanaceae and Crown-of-Thorns belongs to the family Euphorbiaceae.
While comparing scientific classification, Brugmansia and Crown-of-Thorns genus and other classification are also important. Also, when you compare Brugmansia and Crown-of-Thorns, other factors should also be taken into considerations like order, subfamilies, tribe, clade etc. First plant's genus is Brugmansia and other plant's genus is Euphorbia. Brugmansia tribe is Datureae and Crown-of-Thorns tribe is Euphorbieae. Brugmansia clade is Angiosperms, Asterids and Eudicots and order is Solanales whereas Crown-of-Thorns clade is Angiosperms, Eudicots and Rosids and order is Euphorbiales. Every plant have subfamilies. Brugmansia subfamilies are, Solanoideae and Crown-of-Thorns subfamilies are Euphorbioideae. In this way you can compare scientific classification of Brugmansia and Crown-of-Thorns and other products also.