Scientists sort plants into groups by their features. One big question is: does it make flowers?
Flowering plants make flowers. The flowers make seeds, usually inside a fruit. Grasses, roses, sunflowers, beans and most trees with broad leaves are flowering plants.
Non-flowering plants do not make flowers. Conifers, such as pine and fir trees, make seeds inside cones and usually have needle-shaped leaves. Ferns and mosses do not make seeds at all. They grow from tiny spores and usually live in damp, shady places.