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Introduction

Vascular, seedless plants are most commonly visualized as ferns and horsetails.

These plants usually don't grow more than five feet tall, although some horsetails can reach

greater proportions.  In the evolution of plants, vascular seedless plants came after the Bryophytes,

which were nonvascular plants. Vascularization involved the development of stemmed leaves, 

nutrient transport system, and true roots, allowing greater complexity in plants.  There are more than 13,000 

different species of vascular seedless plants on the planet, most of which are found in temperate and tropical climates.

These species each occupy its own niche, or role played by an organism in its environment, and have evolved

 different individual characteristics in order to adapt to their roles (Raven & Johnson).