"Neil Jones" wrote in message
m...
Andy Hall wrote in message
. ..

That's no real issue and can easily be removed. I quite like to see
a certain amount of lichens on roof tiles. It makes them look more
interesting.....


Apparently lichens only grow in places of low atmospheric pollution,
so it's a good indicator of air quality, as well as any aesthetic
benefit.

but is the same true about moss? In fact, are moss and lichen synonymous?
I know that lichens are rarer than they once were.

I'm sitting working looking at the roof of the house opposite, and this is
liberally covered in mosses. This is sunny Twickenham, not that far out of
London and close to the Heathrow flightpaths and one of London's arterial
road, so whereas this might not be an area particularly high in atmospheric
pollution it certainly isn't the cleanest environment.

I've taken the liberty of crossposting this to uk.rec.gardning, in the hope
that one of their knowledgeable netizens may be able to throw some light on
the question.



--
Richard Sampson

email me at
richard at olifant d-ot co do-t uk

On Fri, 9 Jan 2004 12:56:15 -0000, "RichardS" noaccess@invalid
wrote:

"Neil Jones" wrote in message
om...
Andy Hall wrote in message
...

That's no real issue and can easily be removed. I quite like to see
a certain amount of lichens on roof tiles. It makes them look more
interesting.....


Apparently lichens only grow in places of low atmospheric pollution,
so it's a good indicator of air quality, as well as any aesthetic
benefit.

but is the same true about moss? In fact, are moss and lichen synonymous?
I know that lichens are rarer than they once were.

I'm sitting working looking at the roof of the house opposite, and this is
liberally covered in mosses. This is sunny Twickenham, not that far out of
London and close to the Heathrow flightpaths and one of London's arterial
road, so whereas this might not be an area particularly high in atmospheric
pollution it certainly isn't the cleanest environment.

I've taken the liberty of crossposting this to uk.rec.gardning, in the hope
that one of their knowledgeable netizens may be able to throw some light on
the question.

I just discussed with SWMBO, who is a zoology graduate, but has also
studied plant life extensively.

There are a whole spectrum of lichens and some will grow in moderately
polluted conditions. Others are more sensitive to conditions, so for
example you will see a richer set of lichens in a forest in Wales than
you will in town.

They are a composite organism from a fungus and algae, bacteria or
both.

http://www.lichen.com/biology.html

Mosses are rather different, in that theyare plants and produce
chlorophyll themselves and are generally attracted to places where
there is moisture - hence finding them in gutters...

Clearly it makes sense to remove moss from gutters to avoid them
cloggin and water running down the walls, but there is no reason to
remove them or lichens from roofs. Arguably there is more risk of
damage from blasting with a pressure washer or from use of chemicals.




..andy

To email, substitute .nospam with .gl

The message
from "RichardS" noaccess@invalid contains these words:

Apparently lichens only grow in places of low atmospheric pollution,
so it's a good indicator of air quality, as well as any aesthetic
benefit.

but is the same true about moss? In fact, are moss and lichen synonymous?
I know that lichens are rarer than they once were.

No. Moss is a bryophyte, a true plant. Lichen is a symbiotic union of an
alga and a fungus - an unlikely combination as algae are plants and
fungi are in a completely separate order.

I must say that I haven't noticed any evidence of lichens being any less
common than they were, and I've been interested in them since the early
'fifties.

I'm sitting working looking at the roof of the house opposite, and this is
liberally covered in mosses. This is sunny Twickenham, not that far out of
London and close to the Heathrow flightpaths and one of London's arterial
road, so whereas this might not be an area particularly high in atmospheric
pollution it certainly isn't the cleanest environment.

Mosses require some sort of soil to start with, and moisture with it.
Some mosses can dry out for long periods and be revitalised by a shower
of rain, and it is these which you'll find on roofs.

very often their shrinking in dry periods dislodges them, and they can
then colonise damper areas, either in the gutter or on the ground.

--
Rusty
Open the creaking gate to make a horrid.squeak, then lower the foobar.
http://www.users.zetnet.co.uk/hi-fi/

The message
from "RichardS" noaccess@invalid contains these words:

Apparently lichens only grow in places of low atmospheric pollution,
so it's a good indicator of air quality, as well as any aesthetic
benefit.

but is the same true about moss? In fact, are moss and lichen synonymous?
I know that lichens are rarer than they once were.

No. Moss is a bryophyte, a true plant. Lichen is a symbiotic union of an
alga and a fungus - an unlikely combination as algae are plants and
fungi are in a completely separate order.

I must say that I haven't noticed any evidence of lichens being any less
common than they were, and I've been interested in them since the early
'fifties.

I'm sitting working looking at the roof of the house opposite, and this is
liberally covered in mosses. This is sunny Twickenham, not that far out of
London and close to the Heathrow flightpaths and one of London's arterial
road, so whereas this might not be an area particularly high in atmospheric
pollution it certainly isn't the cleanest environment.

Mosses require some sort of soil to start with, and moisture with it.
Some mosses can dry out for long periods and be revitalised by a shower
of rain, and it is these which you'll find on roofs.

very often their shrinking in dry periods dislodges them, and they can
then colonise damper areas, either in the gutter or on the ground.

--
Rusty
Open the creaking gate to make a horrid.squeak, then lower the foobar.
http://www.users.zetnet.co.uk/hi-fi/

The message
from "RichardS" noaccess@invalid contains these words:

Apparently lichens only grow in places of low atmospheric pollution,
so it's a good indicator of air quality, as well as any aesthetic
benefit.

but is the same true about moss? In fact, are moss and lichen synonymous?
I know that lichens are rarer than they once were.

No. Moss is a bryophyte, a true plant. Lichen is a symbiotic union of an
alga and a fungus - an unlikely combination as algae are plants and
fungi are in a completely separate order.

I must say that I haven't noticed any evidence of lichens being any less
common than they were, and I've been interested in them since the early
'fifties.

I'm sitting working looking at the roof of the house opposite, and this is
liberally covered in mosses. This is sunny Twickenham, not that far out of
London and close to the Heathrow flightpaths and one of London's arterial
road, so whereas this might not be an area particularly high in atmospheric
pollution it certainly isn't the cleanest environment.

Mosses require some sort of soil to start with, and moisture with it.
Some mosses can dry out for long periods and be revitalised by a shower
of rain, and it is these which you'll find on roofs.

very often their shrinking in dry periods dislodges them, and they can
then colonise damper areas, either in the gutter or on the ground.

--
Rusty
Open the creaking gate to make a horrid.squeak, then lower the foobar.
http://www.users.zetnet.co.uk/hi-fi/

In article ,
Jaques d'Alltrades wrote:
The message
from "RichardS" noaccess@invalid contains these words:

Apparently lichens only grow in places of low atmospheric pollution,
so it's a good indicator of air quality, as well as any aesthetic
benefit.

but is the same true about moss? In fact, are moss and lichen synonymous?
I know that lichens are rarer than they once were.

No. Moss is a bryophyte, a true plant. Lichen is a symbiotic union of an
alga and a fungus - an unlikely combination as algae are plants and
fungi are in a completely separate order.

Kingdom, actually.

How unlikely would you consider mitochondria and chloroplasts?

I must say that I haven't noticed any evidence of lichens being any less
common than they were, and I've been interested in them since the early
'fifties.

I think that it depends where you are. I have heard that they have
gone down badly in what were rural areas but now are not, like the
Peak District.


Regards,
Nick Maclaren.

In article ,
Jaques d'Alltrades wrote:
The message
from "RichardS" noaccess@invalid contains these words:

Apparently lichens only grow in places of low atmospheric pollution,
so it's a good indicator of air quality, as well as any aesthetic
benefit.

but is the same true about moss? In fact, are moss and lichen synonymous?
I know that lichens are rarer than they once were.

No. Moss is a bryophyte, a true plant. Lichen is a symbiotic union of an
alga and a fungus - an unlikely combination as algae are plants and
fungi are in a completely separate order.

Kingdom, actually.

How unlikely would you consider mitochondria and chloroplasts?

I must say that I haven't noticed any evidence of lichens being any less
common than they were, and I've been interested in them since the early
'fifties.

I think that it depends where you are. I have heard that they have
gone down badly in what were rural areas but now are not, like the
Peak District.


Regards,
Nick Maclaren.

In article ,
Jaques d'Alltrades wrote:
The message
from "RichardS" noaccess@invalid contains these words:

Apparently lichens only grow in places of low atmospheric pollution,
so it's a good indicator of air quality, as well as any aesthetic
benefit.

but is the same true about moss? In fact, are moss and lichen synonymous?
I know that lichens are rarer than they once were.

No. Moss is a bryophyte, a true plant. Lichen is a symbiotic union of an
alga and a fungus - an unlikely combination as algae are plants and
fungi are in a completely separate order.

Kingdom, actually.

How unlikely would you consider mitochondria and chloroplasts?

I must say that I haven't noticed any evidence of lichens being any less
common than they were, and I've been interested in them since the early
'fifties.

I think that it depends where you are. I have heard that they have
gone down badly in what were rural areas but now are not, like the
Peak District.


Regards,
Nick Maclaren.

The message
from (Nick Maclaren) contains these words:

No. Moss is a bryophyte, a true plant. Lichen is a symbiotic union of an
alga and a fungus - an unlikely combination as algae are plants and
fungi are in a completely separate order.

Kingdom, actually.

Order, according to my reading, but I'd go for kingdom if given the
choice, as it seems more appropriate.

How unlikely would you consider mitochondria and chloroplasts?

In lichens? Logically, I'd consider chloroplasts and mitochondria
universal, since they are both present in the green and blue-green algae
which make up part of a lichen. The algae in lichens can be cultivated
separately, but AFAIK the fungal element will germinate but not continue
developing to maturity. I presume that mitochondrial DNA is present in
fungi, but chloroplasts are not, hence the value to the fungus of the
symbiotic arrangement.

I must say that I haven't noticed any evidence of lichens being any less
common than they were, and I've been interested in them since the early
'fifties.

I think that it depends where you are. I have heard that they have
gone down badly in what were rural areas but now are not, like the
Peak District.

While I have stopped many times in the Peak District, I've never done so
with lichens in mind. Radio waves, yes.

I hadn't noticed the areas I've stopped in to be even remotely urbanised.

--
Rusty
Open the creaking gate to make a horrid.squeak, then lower the foobar.
http://www.users.zetnet.co.uk/hi-fi/

"RichardS" noaccess@invalid wrote in message
. ..
"Neil Jones" wrote in message
m...
Andy Hall wrote in message
. ..

That's no real issue and can easily be removed. I quite like to see
a certain amount of lichens on roof tiles. It makes them look more
interesting.....

I agree.


Apparently lichens only grow in places of low atmospheric pollution,

That's not true.


but is the same true about moss?

No.

In fact, are moss and lichen synonymous?

No.

Mary

"RichardS" noaccess@invalid wrote in message
. ..
"Neil Jones" wrote in message
m...
Andy Hall wrote in message
. ..

That's no real issue and can easily be removed. I quite like to see
a certain amount of lichens on roof tiles. It makes them look more
interesting.....


Apparently lichens only grow in places of low atmospheric pollution,
so it's a good indicator of air quality, as well as any aesthetic
benefit.

but is the same true about moss? In fact, are moss and lichen synonymous?
I know that lichens are rarer than they once were.

I'm sitting working looking at the roof of the house opposite, and this is
liberally covered in mosses. This is sunny Twickenham, not that far out
of
London and close to the Heathrow flightpaths and one of London's arterial
road, so whereas this might not be an area particularly high in
atmospheric
pollution it certainly isn't the cleanest environment.

I've taken the liberty of crossposting this to uk.rec.gardning, in the
hope
that one of their knowledgeable netizens may be able to throw some light
on
the question.




Andy, Jaques, Mary, Nick,

many thanks - moss and lichen stuff was interesting.

I didn't quite expect the thread to wander off onto heated discussion about
pollution and vehicle motive power, but you never can tell with usenet (to
paraphrase Winnie the Poo). Sorry about that!

--
Richard Sampson

email me at
richard at olifant d-ot co do-t uk