Re: _Heliamphora_

Jan Schlauer (zxmsl01@studserv.zdv.uni-tuebingen.de)
Fri, 7 Jan 1994 13:40:26 +0100

Andreas, you wrote:

>I doubt whether it's possible to put H. neblinae into the taxon H.
>tatei. In fact both plants grow very far apart from each other! Could
>it not be that they just look similar by chance,without a direct
>relationship???

_H.tatei_var.tatei_ and _H.tatei_var.neblinae_ are not only connected by
morphological but also by geographic intermediates as _H.tatei_ is not
restricted to Mt.Duida in the strict sense. There are populations of
_H.tatei_ on Mt. Huachamacari and Mt. Aracamuni, extending the whole range
of this species to such a degree that _H.tatei_var.neblinae_ becomes just a
variety endemic to the extreme south (not "very far apart" from the other
populations).

In a genus as polymorphic and geographically restricted as _Heliamphora_,
it is not very probable that two populations which are not closely related
to each other should look similar and occupy neighbouring ranges "just by
chance". And certainly, the two varieties are (morphologically and
geographically) closer to each other than to the rest of the genus.

The inclusion of _H.neblinae_ in _H.tatei_ was the result of thorough
examination of living specimens (STEYERMARK himself studied and collected
both varieties in the field) as well as on the basis of rather copious
herbarium material. STEYERMARK gives an extensive account on the reasons
why the two cannot be separated specifically in his realignment.

>Perhaps they both stand quite close to a more primitive form of
>Heliamphora from which the other taxa have evolved.

It seems _H.tatei_ is quite complex a species. In fact, it is the only
"true" carnivore known so far in that genus (the possession of digestive
enzymes has been demonstrated in the paper by MICHELANGELI & AL. which I
have mentioned on this list some time ago). I cannot judge whether this is
primitive or derived within _Heliamphora_:

If it is the plesiomorphous character state, it may have been lost in the
eastern species by secondary reduction, thus rendering them derived.

On the other hand if digestive enzymes are a "new" trait only acquired by
the western _H.tatei_ as an apomorphy, this would be an argument in favour
of a derived status of this species.

I can see no reason why the two varieties of _H.tatei_ should be of
paraphyletic origin derived from "different ends" of a more primitive form
(which should be the +/- direct ancestor of the other, i.e. nowadays the
eastern species as well).

Indeed, morphology and recent distribution indicate monophyletic origin of
_H.tatei_ from a common ancestor (representing a "side branch" separated
from the rest of the genus) to me.

Kind regards
Jan