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