(no subject)

Sat, 12 Nov 1994 14:54:38 -0600 (CST)

Clarke Brunt wrote:
...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.
Many plants with pairs of leaves that are fused to form a cup
around the stem have been reputed to be carnivorous. For most
of these species, it's probably functioning more as a moat to
keep small insects from traipsing up and down the stem... at
least that seems to be the function in Silphium perfoliatum,
the cup plant of American prairies. Remember, the development
of carnivory is a response to nutrient-poor conditions, and
teasel and cup plant both like reasonably good soils.

BTW, teasel heads were used for "fulling" fabric; brushing it
to bring up the nap, and thus increase the warmth and softness.
"Fuller's" used the hooks on the heads for this purpose before
the fine wire bristled brushes were invented. Fuller's earth
was also used-- it's an absorbent clay -- for cleaning the

Has the nutritional status of Roridula (Roridulaceae or Byblidaceae)
been confirmed? Is it getting nutrients from the insects it
traps, or is it just "fly paper"? (sometime, I've gotta go see
one for myself!)

Kay Klier Biology Dept UNI klier@cobra.uni.edu