Vascular plants are larger than non-vascular plants, and more ecologically and morphologically diverse. The ability to transport materials internally allowed plant lineages with vascular tissues to become more complex over time and to develop specialized structures, like roots, stems, and leaves.

Seedless Vascular Plants
The earliest vascular plants reproduced without seeds. This group dominated the first flush of plant life on land, forming dense forests and thickly vegetated swamps all over the globe. Today, only a few living groups of seedless vascular plants remain.

Whisk ferns (psylophytes) are simple leafless plants that bear spore-forming organs directly on the stems.

Horsetails (spenophytes) have straight, jointed stems bearing a whorl of small branches at each joint. Spores are produced from a cone at the tip of the stem.

Club mosses and scale trees (lycophytes) are mainly low-growing and ever-green, with spore-producing cones clustered on the side or tips of their stems.

Ferns (pteropsids) are the most successful and diverse living group of vascular but seedless plants. Unlike the other groups, ferns have true leaves and robust growth. More than 20,000 species grow in a wide range of habitats. They are especially common in harsh conditions that discourage flowering plants. Fern spores are produced on the underside of the leaves.

Seeded Vascular Plants – Gymnosperms
The gymnosperms were the first seed plants, arising about 350 million years ago. The ability of seeds to disperse widely and wait out unfavorable conditions allowed early seeded plants to spread far and wide. The word gymnosperm means naked seeds. The seeds are not enclosed in a protective covering but rather lie exposed on the bracts of the hard woody female cone.

Modern gymnosperms include about 1000 species divided among 3 major groups, the cycads, the ginkgoes, and the conifers.

Cycads (300+ species) are vaguely palm tree-like in appearance, with a bulky trunk topped by a crown of large compound leaves. Cycads are most common in tropical regions. Although these plants are tolerant of difficult conditions, they are declining in the wild due to collecting and habitat destruction.

The ginkgo (1 species) is a large tree bearing distinctive fan-shaped leaves. It grows wild only in a few mountainous areas of China, but is wide-spread as a cultivated plant. Extracts of gingko leaves are sometimes touted as memory aids, but their value has not been demonstrated scientifically.

Conifers (600+ species) are more commonly called pines. They are generally plants with straight trunks, horizontal branches, and needle- or scale-shaped leaves. Most are evergreen. Male cones produce pollen, which is blown by the wind to female cones that bear the eggs and seeds. Conifers are a diverse and cosmopolitan group, abundant in the wild and also extensively cultivated for their wood and for ornamental use.

Seeded Vascular Plants – Angiosperms
Angiosperms, or flowering plants, have been the dominant kind of plant for the last 100 million years. There are more than 250,000 species exhibiting a breath-taking and often bewildering array of forms.

Angiosperms are vital to human life. Almost all the plants we eat are angiosperms, as are almost all the plants we feed to livestock. Angiosperms also supply fibers, paper, fuel, medicines, and wood.

The word angiosperm refers to enclosed seeds – all angiosperm seeds develop inside an ovary. In addition, all the seeds of this group have an endosperm, a thick layer of starchy tissue that nourishes the developing plant. Despite the name, the defining and driving feature of angiosperms is the possession of flowers. The co-evolution of flowers and their pollinators has been an engine of diversity and expansion in both groups.

The internal taxonomy of angiosperms is in flux. Traditional schemes saw two major divisions, the monocots and the dicots, while modern work based on phylogeny recognizes as many as eight. A few of these include:

Nymphaeaceae – water lilies and their relatives, aquatic plants with floating flowers.

Magnoliids – primitive angiosperms having large flowers with undifferentiated petals. The group includes magnolias and many spice plants (black and white pepper, nutmeg, bay leaves, camphor, and cinnamon).

Monocots – plants with one embryonic leaf and leaves with parallel veins, such as lilies, palms, orchids, grasses, and corn, onions, and bananas. Most are herbaceous (stems die back to the ground after growing season).

Dicots or Eudicots – plants with two embryonic leaves. More than 75% of all angiosperms are dicots, about equally split between herbaceous plants and shrubs/trees.