Dr. Harold Webster

I had first met Dr. Webster at the Wapiti Audubon Society meetings, but had
not know he was an expert in mosses. ENTS were well represented at the talk
wit Dale Luthringer, Anthony Kelly, (and Jacqui Noel), Carl Harting, and
Myself. I knew very little about mosses aside from what I had read in some
field books. Most of the references I had found when discussing this topic
earlier this spring were either too simplistic or too complicated to
understand without an adequate background.

Several of us arrived early and Dr. Webster and us scouted several areas
near the Log Cabin Inn nature center. The program started at 3:00 with
those of us listed above and three other people from the general public -
this was really a better response than Hank had expected. He went over the
life cycle of the mosses and liverworts briefly. They both can reproduce
sexually and asexually. The characteristics of various reproductive stages
and growths are often important in the differentiation of different species.

Coral Fungus against a backdrop of moss

After a brief introduction we all headed out into the field. We didn't
travel far because mosses and liverworts grow everywhere. With everyone
using hand lenses, Dr. Webster showed us examples of a number of different
species of mosses and liverworts and pointed out distinctive
characteristics. Many could only be broken down to genera in the field
using hand lenses. Microscopic work would be needed to specifically
identify the species. It was really useful to have someone point out in the
field using actual specimens various physical characteristics present in the
specimens. The entire walk embraced a few hundred yards and we looked at a
couple dozen different mosses and liverworts.

After the talk, all of the ENTS accompanied Dr. Webster to the vicinity of
the Seneca Pine in the Forest Cathedral area to look at the thick moss mats
present there. There are boulders in the area covered by moss. It is a
larger species, and if I read my notes correctly, Polytrium ohioense   I had
chosen this destination for the group because of the large amount of moss
present, the fact that it was in an old growth area, and the existence of
large sandstone blocks, and fallen logs in various states of decay. I
wasn't sure about the diversity of species, just that there was quite a bit
of moss.

Moss topping boulders under the Seneca Pine

I learned a many things and have a better perspective on mosses and
liverworts. Still, as with all trips of this nature, more questions were
raised than answered. Someone ask "Howe old were these moss mats atop the
boulders?" Good question. Mosses are non-vascular, spore producing
organisms. They do not have true roots. If you look at an individual plant
you can see the evidence of annual growth. These examples were perhaps
three inches in length. The living portion of the organism was perhaps 8 to
ten years old. The thing is however, that the bottom portion of the moss
was in the process of decaying at the same time as the upper portion was
growing. The actual height of the moss was dependant of the balance of the
rate of decay and growth.    This particular organism may have been alive
for decades, hundreds of years, or even thousands, but the portions of this
organism living at those times have since decayed. So how old are they?

The rock likely was not covered by moss 10,000 years ago because of the
periglacial climate present in the area. However soon after the glaciers
began to retreat moss could have first grown on this rock. Has it died and
repopulated the rock since that time? Maybe. periods of drought may have
hurt the moss, but are unlikely to have killed it. The tops of the boulders
are typically a xeric environment, but moss that has been dried for years
will start to grow again when wetted. Forest fires could have burned the
moss at some point in the past. Clearly the environment and moss growths
seem to be in some form of a long-term steady state. This is an area of the
forest undisturbed by logging. The little moss growing on that rock could
be a colony of individuals who are each older than the oldest pines in the
forest. The Seneca Pine giving shade to the rock could be nothing but a
fledgling with respect to the ages of the moss. Hank observed that the
mosses are generally not subject to browsing by insects and deer. That is
true they are not commonly eaten. Over the 500 million years of their
existence they have evolved a series of nasty chemicals that make them taste
bad. He said there was one chemical formally known only to occur in
spiders, that was found to occur is some moss species.

I wonder if they may also have some anti-plant characteristics also. There
typically are several species of moss, liverworts, and lichen growing in a
patch on the forest floor. There are a few tiny sprouts of red maple or
hemlock among the moss, but these rarely are more than a fraction of an inch
in height. If were easy to colonize within these mats of moss on rocks, or
on the forest floor, why were they not overwhelmed by angiosperms long ago?
On some boulders hemlock has managed to sprout. On these rocks the moss has
died. The surface is covered by a thin layer of soil, followed by debris of
fine branches, hemlock needles, and cones beneath the trees. What has
killed the moss? Alleopathy is a characteristic of hemlock. It gives off
chemicals that suppress the growth of other plants. This likely has killed
the moss. The boulders have a limited amount of soil, difficult rooting,
and are subject to drying. Those trees that do survive atop the boulders
will grow to a certain height be fore stopping. They are suppressed by
these limitations. That is why trees growing atop a series of rocks all may
seem similar in height, even though they obviously vary in age. Back to the
hemlock on the boulders. This hemlock killed the moss on a particular rock.
If it is blown over or dies, the rock potentially could be recolonized by
moss again. Perhaps this cyclical process has restarted the moss again and
again, resetting the age of the mat.

There are dozens of microenvironments that affect the growth of a particular
species of moss, as well as the circumstance of first come first served. It
would be an impossible task to try to delineate each of these micro
environments that may only be a few centimeters in size. On the original
field trip there was a moss that typically grew on rotting logs, Here on a
shaded sandstone cliff was the same species covering a vertical face. Why?
Dr. Webster is retiring in a year. perhaps then he will have time to do
some needed field work in the Cook Forest State Park. Bryologists are not a
common specialty.

Fallen Cucumber Tree after 18 months

After leaving this area we hiked down to the potentially 400+ year old
fallen cucumber tree. Since its fall a year and a half ago, the decay
process has started. Moss now grows on the western side of the fallen log
almost to the top. Moss grows along some of the branch whorls near the top
of the tree. The smaller branches are beginning to decay. In the center of
a hollow in the fallen trunk, what last year was light reddish slightly
decayed wood, has now turned dark brown and become finer. Small plants are
starting to sprout in the humus. I will post photos later. Dr. Webster
identified some of the moss species as: Dicranus montanum, Pltygyrins
repens, and Mnium sp. (again my spelling may be off). Also present were
slime molds and a number of unidentified crustose lichens. Fro here we
headed back to the parking lot and went for dinner. Dr. Webster did another
program at the campground later that evening.

One website that has some nice photos of bryophytes is:
http://wisplants.uwsp.edu/bryophytes/index.html

In the way of field guides for mosses, there are few worth while. A recent
book has been published called:   50 Outstanding Mosses and Liverworts of
Pennsylvania and Nearby States by Susan Munch looks to be a good starting
point for people interested in the field. This book with photos has just
been published. Dr. Munch is a professor at Albright College in Reading
Pennsylvania. Mosses are generally widely distributed. Dr. Webster talked
of one he had collected in Barrow Alaska and also in the steps of an Aztec
pyramid in Mexico City. So it would be appropriate for people across the
eastern US. It can be ordered from the author at: sus-@alb.edu

I haven't ordered my copy yet, so I don't know any more info that that.

Ed Frank

Michele