Re: What is a carnivorous plant?

Peter Cole (
Thu, 08 Jun 1995 23:11:43 GMT

Jan Schlauer writes:
> Peter,

>> (Jan, I suspect you will have an opinion on this :)

> As you will find in the archives, this question (cf. subject) has been
> discussed at some length on this list in the past. I hope you will find it
> sufficient that I do *not* regard any Bromeliacea as cp

Interesting. I haven't read the American Naturalist article
by Givnish et al. describing their supposed/suggested carnivory
though (getting hold of technical papers or non-UK publications
appears to be beyond the wit of our branch libraries here in
Wales.) Not being a botanist, I'm not really competent to
evaluate the argument anyway, so I am not acquainted with the
reasons for their conclusion (beyond supposed "tank-fluid odour"
or somesuch.) It just seems strange that they should single out
only these three species from the two genera. I'm afraid I don't
have the 1986 CPN with your article either, so my understanding of
your counter-argument is also limited - please excuse me if I
mistakenly ascribe criteria to your definition that are inaccurate.

> (they are
> bromeliads, sometimes forming water cisterns, which is a satisfactory
> description of their features, cf. _Dipsacus_). For further discussion I
> recommend the bromeliad list, not this one.

> BTW: The statement that _Sarracenia_ is devoid of (own) digestive enzymes
> is rather certainly wrong.

Umm, presumably that means that S. purpurea specifically *does*
produce enzymes like all other Sarracenias?

> Endogeneous proteolytic activities have even
> been discovered in the pitcher fluid of some species of _Heliamphora_ (!)
> recently.

"Some"?!? Does that means there are others that don't? If this
is the case, are all heliamphoras carnivorous?
I'm still not quite sure I understand the *exact* criteria you use
to classify a plant as carnivorous - it appears to be that enzymes
are a mandatory prerequisite for the description "carnivorous".
I get the feeling I must be missing something though, since that
seems to be a little problematic with Heliamphoras etc. and any
other bacterial digestors (if there are such things, and unless
in fact they *all* secrete enzymes after all?)

Still a little confused,


> Kind regards
> Jan