The Vascular Plants (Tracheophytes)

Tracheophytes are plants that have evolved active transport mechanisms using special structures to move water & nutrients around their structures. Having the ability to move water & food around meant that these plants could build bigger & more complex architectures. Plants could also now grow in areas that were dryer than before; this extended their range on land. These vascular tissues have evolved into a grand plumbing system with two types of pipes:

1. Xylem cells form tubes that carry water & soil nutrients up from the roots through the rest of the plant.

2. Phloem cells form tubes that move food & nutrients created in the foliage through photosynthesis down to all parts of the plant bellow.

The Vascular plants are divided further into two groups by the way they reproduce.

Plants that do not have seeds (instead they have spores). These plants are vascular plants (that have a plumbing system) & grow to considerable size though they lack true wood. Instead many of the plants in this group need to grow in relatively moist areas so that their short lived spores can germinate easily. Spores are used as a source of reproduction for primitive members of the vascular plants. Like seeds these plants use spores to propagate themselves or as a form of survival when poor conditions kill off their parents.

Plants without seeds include:

Clubmosses (Lycopodiopsida) - are similar to Mosses & the other first vascular plants. They are often encountered in Southern California as Selaginella species. These plants often grow in open exposed areas only growing when their tissues are hydrated by rain.

Horsetails (Equisetaceae) – these reed like plants are found around the globe growing near fresh water. These primitive plants once dominated the forest of the ancient world (they grew up to 150 feet tall). These plants produce spores in cone like structures at mature stems. Unlike other plants Horsetails have a high amount of silica in their tissues.

Ferns (Pteridophyta) - constitute a large portion of the plants that reproduce via spores. Ferns are among the most advance members of the spore bearing plants. Ferns dominated the landscape during the time of the dinosaurs. Ferns have had a long time to evolve into many different shapes, sizes, as well as being able to grow in nearly every plant community on the globe ( we even have ferns in the desert). Out of all the spore bearing plants ferns are the most widely grown for both horticultural & agriculture purposes.