The scientific classification of Foxtail Grass 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. Foxtail Grass and Crown-of-Thorns kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Foxtail Grass and Crown-of-Thorns family is a major factor of Foxtail Grass 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. Foxtail Grass belongs to the family Poaceae and Crown-of-Thorns belongs to the family Euphorbiaceae.
While comparing scientific classification, Foxtail Grass and Crown-of-Thorns genus and other classification are also important. Also, when you compare Foxtail Grass and Crown-of-Thorns, other factors should also be taken into considerations like order, subfamilies, tribe, clade etc. First plant's genus is Alopecurus and other plant's genus is Euphorbia. Foxtail Grass tribe is Not Available and Crown-of-Thorns tribe is Euphorbieae. Foxtail Grass clade is Not Available and order is Cyperales whereas Crown-of-Thorns clade is Angiosperms, Eudicots and Rosids and order is Euphorbiales. Every plant have subfamilies. Foxtail Grass subfamilies are, Not Available and Crown-of-Thorns subfamilies are Euphorbioideae. In this way you can compare scientific classification of Foxtail Grass and Crown-of-Thorns and other products also.