What Are the Four Phyla of the Plant Kingdom?

To the novice gardener, many plants may seem similar. But there is great variety in appearance, structure and reproductive means from plant to plant. There are several different methods for organizing plants based on these differences, but many botanists rely on a classification system that contains four main phyla. Plants are divided among the phyla based on their structural and reproductive characteristics, but there may be some similarities among the plants in different phyla.

Plants in the moss phylum are non-vascular and do not have seeds, roots or flowers. They do not have stems or leaves either, but are capable of photosynthesis. Mosses do not grow upright, and instead grow in an outward manner, anchoring themselves to a base through which they absorb the necessary nutrients and moisture. Mosses may grow in a variety of climates, including deserts and rain forests, as well as tropical and polar regions. They serve an important ecological role because they are able to grow on rocky surfaces, so they are often the first plant species to move into an area. As they begin to die and decompose, mosses help with the formation of soil that allows other plant species to grow in the area. In addition, mosses help recycle nutrients for forest vegetation and maintain proper moisture levels in the soil.

Like mosses, plants in the fern phylum do not have seeds or flowers, but ferns have a vascular system which is used to carry fluids throughout the plant. Ferns reproduce via spores that are found on the underside of their leaves. According to the American Fern Society, there are over 12,000 species of ferns, and most are perennial. Some, however, are evergreen or deciduous. Ferns grow in a variety of environments, including rocky areas, woodlands and bogs. In general, wild ferns thrive in wooded areas with high humidity. They also do well in soil that is slightly acidic, which helps the plants drain properly and retain moisture. Because of their adaptability, ferns are often used as house or landscape plants. They should be kept in shaded areas, where sunlight is filtered.

Conifers, also known as gymnosperms, are a phylum of vascular plants that contain seeds but do not grow flowers. The seeds are commonly referred to as "naked" because they are not protected by flowers or fruit tissue. Instead, many conifers use a cone-like structure, such as a pine cone, to produce their seeds. Others use a berry-like structure. Conifer plants may grow as either trees or shrubs, and usually have leaves that have a needle-like appearance. Common species of conifer plants include pine, spruce, cedar, fir, yew and juniper. They can grow in a variety of climates, but most species prefer full sun.

Flowering plants make up the most complex phylum in the plant kingdom. Also known as angiosperms, these are vascular plants that contain seeds and flowers. They reproduce by growing their seeds inside an ovary which is located inside their flowers. Once the seed is fertilized, the flower falls off and the seed grows into a fruit. Some flowering plants grow two seed leaves and are known as dicot plants, while others begin with only one seed-leaf and are known as monocots. Most flowering plants are dicots, but some notable monocots include irises, lilies and orchids. Flowering plants can grow in a wide range of environments, but typically require greater care than non-flowering plants to remain healthy.