Good morning folks

I've just found the group and enjoyed browsing around the helpful (&
occasionally not so helpful:-) comments & discussions.

I'm planning my undergraduate dissertation at the moment and would
appreciate any thoughts, input and suggestions that anyone might be
able to make.

I plan to measure the effects of leaf axil pools on reproductive
fitness in Dipsacus fullonum, the Wild Teasel, by measuring pollen &
seed production in 3 groups - one with regularly topped-up leaf axils,
one with drained axils and a control.

Whilst the old question of whether there is any degree of carnivoury in
D fullonum is interesting, I want to try going back a step to see if I
can measure any increase in fitness based just on the presence of axil
pools without trying (at this stage) to pin down a specific mechanism.

There are a few specific questions which have arisen from my reading
about Dipsacus.

1. Is there a clear difference between D fullonum and D sylvestris.
Many US studies refer to D sylvestris and I would expect 2 different
latin names to be different species but I have seen it suggested that
they are synonyms for 1 species. (should I expect long diatribes on
what constitutes a species here? I will read them with interest without
even TRYING to add anything useful!)

2. Does anyone have any experience of dispersal in D fullonum?
Particularly could the seeds survive a trip through the gut of a finch?
Everything I've read seems to suggest the it simply drops seeds
locally, but as it is a coloniser of disturbed ground this method od
dispersal seems inadequate. I may have to spend too much time this
autumn copying Darwin & trying to germinate bird shit!! I guess if it's
good enough for Darwin...
I wonder whether D fullonum could be "hitching a ride" on something
like a thistle by being excreted on disturbed ground which the thistle
seed has floated to by a bird which is eating the seeds of both plants.
This is very speculative, but would be a nice mechanism if it could be
seen in action!

3. Any comments on where people are finding teasels growing (either as
isolated plants or clumps) would be very helpful, as would any
information on what might limit teasel distribution and growth. Around
here (Northampton, UK) where Hemlock (Conium maculatum) grows well it
clearly seems to outcompete the Teasels, but close by there may be
ground where the Hemlock does poorly and the teasels seem to be growing
well.

4. Whilst I said that I'm not looking at carnivoury; any tales of large
or unusual organisms found in Tease axils would be very interesting.
Here they seem to particularly enjoy drowning molluscs. The smell of a
teasel with 4 or 5 decaying molluscs on board is really beyond compare!

I appreciate that I am asking a lot but I am becoming somewhat obsessed
by this fascinating plant and any info would be very warmly received.

Many many thanks

Ian Wilson

In message , Ian Wilson
writes
Good morning folks

I've just found the group and enjoyed browsing around the helpful (&
occasionally not so helpful:-) comments & discussions.

I'm planning my undergraduate dissertation at the moment and would
appreciate any thoughts, input and suggestions that anyone might be
able to make.

I plan to measure the effects of leaf axil pools on reproductive
fitness in Dipsacus fullonum, the Wild Teasel, by measuring pollen &
seed production in 3 groups - one with regularly topped-up leaf axils,
one with drained axils and a control.

Whilst the old question of whether there is any degree of carnivoury in
D fullonum is interesting, I want to try going back a step to see if I
can measure any increase in fitness based just on the presence of axil
pools without trying (at this stage) to pin down a specific mechanism.

There are a few specific questions which have arisen from my reading
about Dipsacus.

1. Is there a clear difference between D fullonum and D sylvestris.
Many US studies refer to D sylvestris and I would expect 2 different
latin names to be different species but I have seen it suggested that
they are synonyms for 1 species. (should I expect long diatribes on
what constitutes a species here? I will read them with interest without
even TRYING to add anything useful!)

INRA, URL:http://www.dijon.inra.fr/flore-france/di-dn.htm has D.
sylvestris as a synonym of D. fullonum.

2. Does anyone have any experience of dispersal in D fullonum?
Particularly could the seeds survive a trip through the gut of a finch?
Everything I've read seems to suggest the it simply drops seeds
locally, but as it is a coloniser of disturbed ground this method od
dispersal seems inadequate. I may have to spend too much time this
autumn copying Darwin & trying to germinate bird shit!! I guess if it's
good enough for Darwin...
I wonder whether D fullonum could be "hitching a ride" on something
like a thistle by being excreted on disturbed ground which the thistle
seed has floated to by a bird which is eating the seeds of both plants.
This is very speculative, but would be a nice mechanism if it could be
seen in action!

I've assumed, on no good grounds, that seeds of teasel are dispersed by
attaching to the plumage/pelage of animals.

3. Any comments on where people are finding teasels growing (either as
isolated plants or clumps) would be very helpful, as would any
information on what might limit teasel distribution and growth. Around
here (Northampton, UK) where Hemlock (Conium maculatum) grows well it
clearly seems to outcompete the Teasels, but close by there may be
ground where the Hemlock does poorly and the teasels seem to be growing
well.

4. Whilst I said that I'm not looking at carnivoury; any tales of large
or unusual organisms found in Tease axils would be very interesting.
Here they seem to particularly enjoy drowning molluscs. The smell of a
teasel with 4 or 5 decaying molluscs on board is really beyond compare!

I appreciate that I am asking a lot but I am becoming somewhat obsessed
by this fascinating plant and any info would be very warmly received.

Many many thanks

Ian Wilson

--
Stewart Robert Hinsley

A google.com search on Dipsacus dispersal produces a lot of hits. It is
an invasive species in the U.S. and Canada so has been studied a lot.

The study "Dispersal of Dipsacus laciniatus seed along an interstate
corridor and a natural area" by R. N. Wiedenmann ) and
A. Musser, Illinois Natural History Survey and J. D. Parrish, Millikin
University concluded it was wind dispersed and traveled a maximum of 15
meters along a highway.

http://66.102.7.104/search?q=cache:V...ispersal&hl=en

The following webpages indicates other important modes of dispersal as
water, highway mowing equipment, highway construction, cultivation and
humans disposing of flower arrangements containing teasel. It has
spread particularly along the interstate highway system. Its use in
flower arrangements is blamed for its spreading to cemetaries.

http://dnr.wi.gov/invasives/fact/teasel_com.htm
http://www.inhs.uiuc.edu/chf/outreach/VMG/teasel.html
http://www.mdc.mo.gov/nathis/exotic/vegman/ten.htm

Dipsacus fullonum L. was named by Linneaus (1707-1778). William Hudson
(1730-1793) seemingly believed D. sylvestris Huds. represented a
separate species because the bracts on the receptacle have a straight
barbed awn according to Bailey's Manual of Cultivated Plants. D.
fullonum seems to have a recurved awn. Such a minor difference is
apparently not considered enough to represent a separate species by
most taxonomists today so D. sylvestris is either a subspecies,
Dipsacus fullonum subsp. sylvestris, or merely a synonym for D.
fullonum. The references that are listing D. sylvestris seem out of
date. Britton and Brown's influential 1913 flora listed D. sylvestris
as did Asa Gray's 1908 Manual of Botany so that may have given the name
staying power. You might try to look up Hudson's original description
for D. sylvestris and see why he thought it was a separate species from
D. fullonum or if it was merely a case of his independently describing
the same species as Linnaeus given that were contemporaries.

The following reference says in the U.S., D. sylvestris is used for the
cultivated teasel and D. fullonum for the wild teasel. The opposite is
done in Europe.

http://ucce.ucdavis.edu/files/fileli...5319/17400.pdf

Dipsacus is not usually considered carnivorous because it has no
enzymes to digest trapped animals. I'm not sure if there have been
research studies that examined if the trapped animals provide a benefit
to the plant. I'm sure it's possible that they could provide a small
benefit because foliar fertilization of plants can be beneficial. Tank
bromeliads can drown animals too but they are not usually considered
carnivorous. The phenomenon of plants retaining small, open pools of
water is termed phytotelmata.

http://www.canopyants.com/treehole.html
http://bromeliadbiota.ifas.ufl.edu/bromfit.htm

You might wish to check the following databases for Dipsacus:
http://www.ingentaconnect.com/
http://www.pubmedcentral.nih.gov/
http://agricola.nal.usda.gov/


David R. Hershey

Thanks Stewart - I think I can rest assured that D. sylvestris & D.
fullonum are the same species. Sorting the dispersal seems more of a
task. I look farward to getting some data to clarify what's happening.
Cheers
Ian

In article , Stewart Robert Hinsley
wrote:

URL:http://www.dijon.inra.fr/flore-france/di-dn.htm

Thanks David

Yes - I'd seen the "interstate corridor" paper, but I don't fully buy
the idea that it is D. fullonum's primary natural dispersal method.
Perhaps I have to accept that there isn't a "primary" method but are a
number of lesser methods. I'll keep looking and I'll be checking out
the finch crap come the autumn!

Cutting a couple of heads in half to check on seed development
yesterday I found 2 out of 3 with larvae hollowing out the pith in the
centre. A quick search suggests 1 of 2 or 3 species of moth larvae.
I can't imagine a more protected place for a little grub to live (until
I come along that is!).

Next I have to work out the best way to quantify reproductive fitness.
Ideally I would count every seed on each experimental teasel and then
plant a random sample to find a germination rate. Unfortunately I have
just the one life so I may need to find a way of cutting the work down
to manageable levels.

Alarm bells go off in my head when I read . "A single teasel plant can
produce over 2,000 seeds; up to 30-80% of the seeds may germinate.
Seeds may remain viable for at least 2 years." and then find the same
wording repeated over & over. It just sounds too much as if one
unrefferenced source is being quoted as gospel over and over. Nothing
for it but to get a huge sheet, a teasle plant and some seed trays I
suppose! I just hope the moth larvae aren't having too much effect on
seed production. If they do they will really mess up my plans!!

Thanks for the help - I'll try & remember to post a link to my
dissertation when it's done in 18 months!

Cheers

Ian


In article . com,
wrote:

A google.com search on Dipsacus dispersal produces a lot of hits. It is
an invasive species in the U.S. and Canada so has been studied a lot.

The study "Dispersal of Dipsacus laciniatus seed along an interstate
corridor and a natural area" by R. N. Wiedenmann ) and
A. Musser, Illinois Natural History Survey and J. D. Parrish, Millikin
University concluded it was wind dispersed and traveled a maximum of 15
meters along a highway.


http://66.102.7.104/search?q=cache:V.../ncr125/StateR
pts2002IL.htm+Dipsacus+dispersal&hl=en

The following webpages indicates other important modes of dispersal as
water, highway mowing equipment, highway construction, cultivation and
humans disposing of flower arrangements containing teasel. It has
spread particularly along the interstate highway system. Its use in
flower arrangements is blamed for its spreading to cemetaries.

http://dnr.wi.gov/invasives/fact/teasel_com.htm
http://www.inhs.uiuc.edu/chf/outreach/VMG/teasel.html
http://www.mdc.mo.gov/nathis/exotic/vegman/ten.htm

Dipsacus fullonum L. was named by Linneaus (1707-1778). William Hudson
(1730-1793) seemingly believed D. sylvestris Huds. represented a
separate species because the bracts on the receptacle have a straight
barbed awn according to Bailey's Manual of Cultivated Plants. D.
fullonum seems to have a recurved awn. Such a minor difference is
apparently not considered enough to represent a separate species by
most taxonomists today so D. sylvestris is either a subspecies,
Dipsacus fullonum subsp. sylvestris, or merely a synonym for D.
fullonum. The references that are listing D. sylvestris seem out of
date. Britton and Brown's influential 1913 flora listed D. sylvestris
as did Asa Gray's 1908 Manual of Botany so that may have given the name
staying power. You might try to look up Hudson's original description
for D. sylvestris and see why he thought it was a separate species from
D. fullonum or if it was merely a case of his independently describing
the same species as Linnaeus given that were contemporaries.

The following reference says in the U.S., D. sylvestris is used for the
cultivated teasel and D. fullonum for the wild teasel. The opposite is
done in Europe.

http://ucce.ucdavis.edu/files/fileli...5319/17400.pdf

Dipsacus is not usually considered carnivorous because it has no
enzymes to digest trapped animals. I'm not sure if there have been
research studies that examined if the trapped animals provide a benefit
to the plant. I'm sure it's possible that they could provide a small
benefit because foliar fertilization of plants can be beneficial. Tank
bromeliads can drown animals too but they are not usually considered
carnivorous. The phenomenon of plants retaining small, open pools of
water is termed phytotelmata.

http://www.canopyants.com/treehole.html
http://bromeliadbiota.ifas.ufl.edu/bromfit.htm

You might wish to check the following databases for Dipsacus:
http://www.ingentaconnect.com/
http://www.pubmedcentral.nih.gov/
http://agricola.nal.usda.gov/


David R. Hershey

It's good you are skeptical about uncited internet sources. The 30 to
80% germination rate may even be for cultivated seed because seed
packets list a germination percentage. The following webpage says 3000+
seed per plant and 6+ years viability.
http://www.newton.dep.anl.gov/askasc...9/bio99464.htm


Try to get copies of Werner's papers and then check the Science
Citation Index for more recent work that cites Werner's work.

Werner, P. A. 1975. The biology of Canadian weeds. Dipsacus sylvestris
Huds. Canadian Journal of Plant Science 55: 783-794.

Werner, P. 1975. The effects of plant litter on germination in teasel,
Dipsacus sylvestris Huds. American Midland Naturalist 94: 470-476.

Werner, P. A. 1975. Predictions of fate from rosette size in teasel
(Dipsacus fullonum L.). Oecologia 20: 197-201.
The Oecologia paper is a citation classic:
http://garfield.library.upenn.edu/cl...AJ98800001.pdf

Werner, P. A., and H. Caswell. 1977. Population growth rates and age
versus stage-distribution models for teasel (Dipsacus sylvestris) Huds.
Ecology 58: 1103-1111.


You might even try to contact Werner:
http://www.wec.ufl.edu/faculty/wernerp/

The dispersal method may be different in America than in teasel's
native habitat.

David R. Hershey

Thanks David,

Yes - I've got some of those papers but the Canadian Journal of Plant
Science one & the Oecologia one are both proving harder to get hold of
than the others. I think I need a trip to one or two other universities
with bigger Journal holdings than we have at Northampton. A job for
September once my daughter is back at school I think!

I'm biding my time and trying to gain a degree of knowledge in teasels
before contacting Pat Werner. All my research so far seems to suggest
that she probably knows as much about teasels as anyone so I don't want
to ask something stupid & look foolish!!

The "ask a scientist" page was interesting. A study of the length of
time seeds are viable would be interesting, but is going to be too long
for my disertation. My main study will be next year & will be based on
axil pools. For now though I may spend some time this autumn trying to
get a clear correlation between flower head size and seed
numbers/viability. At some point flowering heads seem to become too
small to produce fully mature looking seeds. If I can get a good
correlation it might even reduce my counting work next autumn!! I'm
expecting to need at least 10 or 12 plants in each of 3 groups. If
plants really do have 3,000 seeds each I might be looking at 90,000
rather hard to extract seeds to count next autumn - so any sort of
short cut I can devise would be wonderful!

Thanks for all the help & suggestions

All the best

Ian



In article . com,
wrote:

It's good you are skeptical about uncited internet sources. The 30 to
80% germination rate may even be for cultivated seed because seed
packets list a germination percentage. The following webpage says 3000+
seed per plant and 6+ years viability.
http://www.newton.dep.anl.gov/askasc...9/bio99464.htm


Try to get copies of Werner's papers and then check the Science
Citation Index for more recent work that cites Werner's work.

Werner, P. A. 1975. The biology of Canadian weeds. Dipsacus sylvestris
Huds. Canadian Journal of Plant Science 55: 783-794.

Werner, P. 1975. The effects of plant litter on germination in teasel,
Dipsacus sylvestris Huds. American Midland Naturalist 94: 470-476.

Werner, P. A. 1975. Predictions of fate from rosette size in teasel
(Dipsacus fullonum L.). Oecologia 20: 197-201.
The Oecologia paper is a citation classic:
http://garfield.library.upenn.edu/cl...AJ98800001.pdf

Werner, P. A., and H. Caswell. 1977. Population growth rates and age
versus stage-distribution models for teasel (Dipsacus sylvestris) Huds.
Ecology 58: 1103-1111.


You might even try to contact Werner:
http://www.wec.ufl.edu/faculty/wernerp/

The dispersal method may be different in America than in teasel's
native habitat.

David R. Hershey

In message , Ian Wilson
writes

The "ask a scientist" page was interesting. A study of the length of
time seeds are viable would be interesting, but is going to be too long
for my disertation. My main study will be next year & will be based on
axil pools. For now though I may spend some time this autumn trying to
get a clear correlation between flower head size and seed
numbers/viability. At some point flowering heads seem to become too
small to produce fully mature looking seeds. If I can get a good
correlation it might even reduce my counting work next autumn!! I'm
expecting to need at least 10 or 12 plants in each of 3 groups. If
plants really do have 3,000 seeds each I might be looking at 90,000
rather hard to extract seeds to count next autumn - so any sort of
short cut I can devise would be wonderful!

Once you have an average weight for seeds you can clean the seeds from a
plant and weigh them. (The problem is non-random variation is seed
weight, i.e. between plants and between flower heads.)
--
Stewart Robert Hinsley

Thanks Stewart

I'll try that - but yes, the variation in size between seeds size from
plant to plant or from head to head might be interesting too. I think I
need to do all I can this year so that come next year I have some sense
of what is a) important and b) possible when I start my disertation!

If I can get a clear correlation between seed production & seed head
size I though I could mostly just count & measure seed heads & then
just count a few plants seeds to give an indication of margin of error.

Thanks for the input - it all helps!

Cheers

Ian



In article , Stewart Robert Hinsley
wrote:

In message , Ian Wilson
writes

The "ask a scientist" page was interesting. A study of the length of
time seeds are viable would be interesting, but is going to be too long
for my disertation. My main study will be next year & will be based on
axil pools. For now though I may spend some time this autumn trying to
get a clear correlation between flower head size and seed
numbers/viability. At some point flowering heads seem to become too
small to produce fully mature looking seeds. If I can get a good
correlation it might even reduce my counting work next autumn!! I'm
expecting to need at least 10 or 12 plants in each of 3 groups. If
plants really do have 3,000 seeds each I might be looking at 90,000
rather hard to extract seeds to count next autumn - so any sort of
short cut I can devise would be wonderful!

Once you have an average weight for seeds you can clean the seeds from a
plant and weigh them. (The problem is non-random variation is seed
weight, i.e. between plants and between flower heads.)