ⓘ Pteridophyta ..


Christmas fern

The Christmas fern, Polystichum acrostichoides, is an evergreen fern. It grows mostly in the eastern part of the United States. Christmas fern usually grows in dense woods and rocky mountains. The name supposedly comes from the plant being still lush and green around Christmas. They usually grow around one to two feet tall. Their fronds grow in circular clumps.



Fern s are a group of about 20.000 species of plants in the division Pteridophyta. Unlike bryophytes, ferns have xylem and phloem, which makes them vascular plants. Most ferns belong to the Class Leptosporangiata or Pteridopsida. This includes most of those you see in gardens and woods. The horsetails belong to another class, the Equisetopsida, which was extremely important in the Carboniferous period. Only one genus survives. The other classes of fern are also quite small today. Ferns do not have waxes or special cells on their surface that keep water from evaporating. They have roots, st ...


Tree fern

Tree ferns are a large group of ferns with tree-like form. They are part of a subclass of ferns which is monophyletic by DNA sequence analysis. The tree-ferns and some other ferns with creeping rhizome stems make up the Cyatheales group of ferns as a sub-class or order. The tree-like habit has evolved a number of times in this group. They can grow up to 20 metres tall, with their large fronds at the top. Tree ferns are found growing in tropical and subtropical areas as well as temperate rainforests in Australia, New Zealand, and other island groups nearby. A few genera extend further, such ...