Herself's Houston Garden

Conservation through cultivation

Modern plants begin in the Silurian Period




443 million years ago to 417 million years ago is the Silurian period. This is where the plants we grow today first appear. The ice is melting, the world is warming and future ice ages and global warming won’t be as dramatic. With the melting ice comes a dramatic rise in sea level. Continents are drifting apart and drifting further from the southern pole of the planet.

Plants that grow upright reaching towards the sun now appear at the edge of the water. The plants strengthen fibers that can support them and hold them upright. They develop tubes to carry the water from their bases to the tops of themselves. All current plants have systems that began here about 430 million years ago.

Now that plants can retain moisture they are slowly venturing away from the water’s edge. The first plant we know of to do so is Cooksonia. It was about 4″ tall, had no leaves and no roots. The stems branched and each branch would end with large round balls containing the spores. These become extinct at the end of the next era ( Devonian ).

We also now have club moss which has 10″ tall stems and very tiny leaves that form on the stems. The leaves are more like scales than what we think of as plant leaves today. Today tillandsia are one of the plants that continues to have scale like leaves.

All of the plants in this time reproduce with spores.

Lichen is busy on the land converting rocks into soil.

But still most of the planet is a barren wasteland and most of life is in the oceans. Only at the water’s edges, ocean, ponds and rivers do we see any life at all.