Lycophytes, Horsetails, Ferns

There is something I forgot to mention in my post about the seedless vascular plants. So I am dedicating this post to the phylum Lycophyta because they are cool!
By the Carboniferous (which was over 300 million years ago) lycophytes, horsetails and ferns existed as small - herbaceous plants, or as giant woody trees with diameters of over 2m and heights over 40m! These giant plants thrived in warm, moist swamps and they created the giant forests of the Carboniferous period. They probably led to their own extinction because such huge forests reduced the carbon dioxide in the atmosphere (carbon dioxide is a green house gas that is partly responsible for Global Warming). In modern times we have Global Warming because there is too much carbon dioxide, since the giant plants decreased the carbon dioxide levels, they created GLOBAL COOLING! But, the giant woody lycophytes, horsetails and ferns became extinct in the cooler and drier environment.
Isn't that just amazing?!!!!!

These are modern, small lycophytes. . . . . . . . . . . . .

And these are the giant forests of the Carboniferous period!

SEEDLESS VASCULAR PLANTS

Seedless vascular plants include the phylum Lycophyta (club mosses, spike mosses, and quillworts) and phylum Pterophyta (true fern, horsetails, and whisk ferns).

Club moss

Spike moss

Spike moss

Ferns

Ferns

Horsetail

Whisk Fern

There is great diversity within these groups. There are 1,200 Lycophytes and 12,000 Pterophytes! That's a lot!