(no subject)

Jan Schlauer (zxmsl01@studserv.zdv.uni-tuebingen.de)
Mon, 7 Feb 1994 20:25:30 +0100


>But just because carnivory in _Catopsis_ and _Brocchinia_ is becoming

Yes, indeed "suspected". This is just not enough for me.

Look, bromeliads as a whole family (not *all* but very many of the species)
are adapted to the uptake of water (incl. ions or organic matter) via the
cisterns formed by leaves clustered in closed (i.e. water tight) rosettes.
In some species (also other than the two genera mentioned above), the
structure as well as physiological details of the glands on the adaxial
(inner) surface of the leaf bases are quite well known. In the cisterns,
very frequently small animals (together with other organic matter) are
trapped and subject to bacterial digestion, with the effect that soluble
components derived from animal tissue can eventually be absorbed by the
plant. Therefore, this whole family may be called an assemblage of
"omnivores" (by necessity including +/- inadvertent carnivores, if you
like). But this just is not the type of carnivory I mean.

> ...does not mean you have to open the floodgates to the others. You
> note that your list is personalized to your whims by the inclusion of
> _Roridula_. There's no reason that you must allow these other species
> just because you allow a few Bromeliads...

Especially in the (very, very numerous) cases of pitfalls or adhesive
traps, several additional criteria (presence of lures, additional trapping
structures, proteolytic enzymes, etc.) have to be fulfilled by really
carni*vorous* plants. Otherwise, we would indeed have to face inclusion of
nearly half the plant kingdom.

I think I can rest satisfied with those carnivorous genera which can be
called such without problems. Even if there are examples of *details* which
are common to cp and non-cp, we can still state the carnivorous *syndrome*
to be present in only a few groups (each of them most probably monophyletic
and carnivorous without exception!), viz the 14 genera _Heliamphora_,
_Sarracenia_, _Darlingtonia_, _Cephalotus_, _Drosophyllum_, _Dionaea_,
_Aldrovanda_, _Drosera_, _Nepenthes_, _Triphyophyllum_, _Byblis_,
_Pinguicula_, _Genlisea_, and _Utricularia_, originating from at least 4,
probably 6 or 7, but at most 8 independent evolutionary lines within the

If you like, you may call other plants "semicarnivores", "precarnivores",
"subcarnivores", or that like, but please do not worry if I am not
interested in these too much, personally. On the other hand I see no reason
why _Brocchinia_, _Proboscidea_, or other plants should not be cultivated
anymore just because they are not called cp.

Kind regards