Mosses are everywhere! But there are no liverworts!
I had intended on this blog post being about mosses and
liverworts. Back home in the deep south,
it can be so hot and dry that the liverworts are very hard to find there. I always look for them when I am up
north. We had a good rain, which really
makes these plants grow like crazy.
Mosses were in abundance, but I could not find the liverworts this
year. I looked in all the places that I
had found them before, but it seems they are hiding from me this year.
As I strolled through the woods today, I noticed that the
mosses were just beautiful.
Mosses are nonvascular plants called Bryophytes, sometimes referred
to as the “in-between” plants. When I am
teaching my students about Bryophytes, I refer to them as the “amphibians of
the plant kingdom”. This really helps my
students remember the key points about the Bryophytes.
Like the amphibians, the Bryophytes live on land, but are
not well adapted to life on land.
First
of all, they do not have any vascular tissue.
Vascular tissue (xylem and phloem) is the conducting tissue within a
plant. Xylem consists of long tubes that
carry water from the roots to the top of the plant. The phloem consists of long tubes that
distribute glucose and other organic compounds from the leaves throughout the
plant. The mosses are nonvascular,
meaning that they do not have xylem or phloem.
Another characteristic that makes the mosses poorly adapted
for life on land is the presence of motile gametes …… a swimming sperm! When it rains, the mosses will rush to
produce reproductive structures because the only way for sperm to reach the egg
is by swimming in rainwater.
The true land plants are tracheophytes. They are well suited to life on land because
they are vascular plants. They have
xylem and phloem to transport food and water long distances. Tracheophytes do not depend on water for reproduction. These plants evolved a much more efficient
sperm delivery system. Pollen!
Tomorrow I am going on a hunt for pitcher plants. There is a bog near our cabin where the
pitcher plants have thrived in years past.
It is extremely dry from lack of rain, so I am keeping my fingers
crossed that the pitcher plants have survived.
Stay tuned …….
