While there are many ways to structure plant classification, one way is to group them into vascular and non-vascular plants, seed-bearing and spore-bearing, and angiosperms and gymnosperms. Plants can also be classified as grasses, herbaceous plants, woody shrubs, and trees. Within the plant kingdom, plants are divided into two main groups. The largest group contains the plants that produce seeds. These are flowering plants (angiosperms) and conifers, Ginkgos, and cycads (gymnosperms). The other group contains the seedless plants that reproduce by spores. The primary purpose of classifying plants is to ensure that the right plants are correctly named, grouped and identified. Plants are classified based on these 3 characteristics: The evergreen plants are plants that retain leaves at all times (all year round). Woody plants can also be grouped as deciduous or evergreen. Plant taxonomy or classification is the science of naming organisms and placing them in a hierarchical structure; each level is given a name (e.g., kingdom, division (phylum), class, order, family, genus, species). Any given organism can be classified throughout the hierarchy.