I have mentioned this in correspondence with Rogan before (we're
both on the CACTI_ETC list too), but maybe the rest of the CPers
have something to contribute.
Dipsacus fullonum is a common 'weed' known as Teasel in the U.K.
I'm not using 'weed' as a disparaging term, as I have intentionally
grown it in my garden. I don't really see it as carnivorous, though
the reservoirs formed by the leaves clasping the flower stem may trap
some insects. Why it should want to collect water in this way, I
don't know.
The spiky seed heads are ornamental, and attractive to finches
(probably the only chance of seeing the European Goldfinch in my
garden). The specific name is something to do with 'Fullers' (who
I think were involved in using felt for hat-making) using the
heads as brushes.
-- Clarke Brunt (clarke@brunt.demon.co.uk)