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