The scientific classification of Tree-of-Heaven and Lamb's Lettuce 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 Lamb's Lettuce kingdom and all other plants kingdom is Plantaea.
Plant family is the group of plants which have something in common. Tree-of-Heaven and Lamb's Lettuce family is a major factor of Tree-of-Heaven and Lamb's Lettuce 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 Lamb's Lettuce belongs to the family Valerianaceae.
While comparing scientific classification, Tree-of-Heaven and Lamb's Lettuce genus and other classification are also important. Also, when you compare Tree-of-Heaven and Lamb's Lettuce, 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 Valerianella. Tree-of-Heaven tribe is Not Available and Lamb's Lettuce tribe is Valerianeae. Tree-of-Heaven clade is Angiosperms, Eudicots and Rosids and order is Sapindales whereas Lamb's Lettuce clade is Angiosperms, Asterids and Eudicots and order is Dipsacales. Every plant have subfamilies. Tree-of-Heaven subfamilies are, Not Available and Lamb's Lettuce subfamilies are Valerianoideae. In this way you can compare scientific classification of Tree-of-Heaven and Lamb's Lettuce and other products also.