Spore-bearing Land Plants
Reminder: Clicking on the picture will take you to the site where I originally found it.
This collection of divisions has two names. One is spore-bearing land plants, and the other is seedless vascular plants. Come on, science people, you can do better than that! In spite of the lack of creativity in naming these guys, there is a lot to be learned.
As the names imply, these plants live onland. They are less dependant on water than the bryophytes. They are vascular, meaning they have developed tubes for transporting liquids and nutrients. They have no seeds, but produce spores instead. And now we've covered the basics, let's look at each of the four divisions.
Psilophyta
The psilophyta division is a very simple vascular plant. As far as plants go, this one has a primitive design. It is rootless, like the bryophytes, and doesn't have any decent leaves. It somewhat resembles moss, but with a big difference - vascular tissue.
There are two types of vascular tissue. Xylem is responsible for transporting water from the ground to the ends of the plant. Phloem is responsible for transporting food from the green leafy parts to the parts underground. In these simple plants, the xylem is a tube in the center of the plant. The phloem surrounds it. You can think of it as a straw within a straw. In the inner straw, water is going up while in the outer straw, nutrients are going down.
The life cycle of psilophyta is a lot like the bryophytes and the ferns. In involves an alternation of generations. Some reproduction is sexual and some is asexual.
Psilophyta are also known as whisk ferns. Don't be confused by the name though. They aren't ferns, any more than snowmen would be classified as Homo sapiens glacialis *.
Lycophyta
Welcome to the lycophytes. These are ancient plants. Currently, the only lycophyte which is common is the club moss. This wasn't always the case. About 400 million years ago, according to the fossil record, the land was dominated by the lycophytes. There were lycophyte trees towering 35 meters (for the Yanks, that's over 100 feet) in the air.
It is believed that lycophytes are a major contributor to the oil and coal found around the earth. It wasn't the dinosaurs, but the plants that provided us with that rich source of energy.
Modern lycophytes are known for having small leaves and a simple mid-vein in each leaf. They reproduce both sexually and asexually. They are a lot like the other vascular seedless plants.
Lycophyes have an unusual feature. They have flammable spores. This alone is kinda cool, but not when people used to bring club mosses into their houses for Christmas. Ya put some nice greenery near the fire and *kablam* ya loose the house. So be careful around lycophytes.
Sphenophyta
I'm personally acquainted with the sphenophytes. There were bunches of them growing along the sides of the creek near my house. We used to call them snake grass, but they're better known as mares tail, horse pipes, scouring rushes or, most commonly, horsetails.
Long ago, there where whole towering forests of sphenophyta, but 350 million years later, there is only one type (genus) - Equisetum. All living sphenophytes are variations on this theme. The common horsetail grows about 1-2 feet high in moist pasture-lands. It has no root system, but its rhizomes go pretty deep. It's fun to play with because the stems are hollow and easily separated. The sphenophyta in Mexico may grow has high as ten feet tall.
Like all these plants, they undergo alternation of generations. The large plant which is easily recognized is the spore producer.
Pterophyta
Human beings are rather silly. We choose favorites in the plant and animal kingdoms. We think squirrels are cute, but hate rats. Lizards are fun, but snakes are bad. Well, here is a human favorite among the vascular spore producers. This division is known as the pterophytes but you'll know them better as ferns.
These are the most recognizable of seedless plants. You may have seen them given as a gift, either by themselves as a housewarming present, or neatly wrapped with a rose and baby's breath. When you get this close to a fern again, turn the leaf over and look for the sori on back.
The fern "leaves" are called fronds, and they're part of the spore producing generation. The sori, or brownish dots on the back of the leaf, are little capsules which hold the spores. Each of the spores can grow into a gametophyte, or sex-cell producing plant. After another generation, this will produce another fern.
A couple more things you should know when studying ferns. First, the immature frond (uh, that leaf thingy) is called a fiddlehead. When it is developing, it starts out all curled up and looks a lot like the knobby end of a violin. The other thing you should know is what the gametophyte looks like. When a fern is in its gamete producing stage, it doesn't look like a fern frond at all. It is flat and shaped somewhat like a heart. You may find these at the base of a wild growing fern.
Back to the bryophyte page,
visit the gymnosperms,
peek at the angiosperms,
back to the main plant page, or
return to the overview.