The scientific classification of Adam's Needle and Oatgrass 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. Adam's Needle and Oatgrass kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Adam's Needle and Oatgrass family is a major factor of Adam's Needle and Oatgrass 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. Adam's Needle belongs to the family Agavaceae and Oatgrass belongs to the family Poaceae.
While comparing scientific classification, Adam's Needle and Oatgrass genus and other classification are also important. Also, when you compare Adam's Needle and Oatgrass, other factors should also be taken into considerations like order, subfamilies, tribe, clade etc. First plant's genus is Yucca and other plant's genus is Danthonia. Adam's Needle tribe is Not Available and Oatgrass tribe is Aveneae. Adam's Needle clade is Angiosperms and Monocots and order is Liliales whereas Oatgrass clade is Angiosperms, Commelinids and Monocots and order is Poales. Every plant have subfamilies. Adam's Needle subfamilies are, Agavoideae and Oatgrass subfamilies are Danthonioideae. In this way you can compare scientific classification of Adam's Needle and Oatgrass and other products also.