Re: CP Evolution

Jan Schlauer (
Fri, 9 Jun 1995 11:20:36 +0100


> I don't get it, explain with more detail. If you say you believe
>the Drosera we see today are relicts of a greater age of these subgenera,
>when they were more widespread in Australia, then where does the above
>statement fit in, with plants diversifying as they're pressed into their
>small areas by the desert. How do the insects fit into this too?

You are right, a shrinking area alone does not necessitate diversification.
We must of course consider the type of area AU _Drosera_ was concentrated
in. As I wanted to stress in my previous posting (maybe without the
expected success), we can observe centres of diversity in the genus _D._ in
the mediterranean zones of AU and AF (and remarkably *not* AM!). In both,
AU and AF we can assume that the genus has originally been "forced" into
these habitats, and at least in AU this force resulted in concentration.
Some of the taxa now endemic or subendemic in SW AU or S AF were more
widespread previously. These are the old elements I have been talking about
(paleoendemics, relicts).

Establishment of these in the mediterranean climate (_Drosera_ is
presumably of temperate "post-S-Gondwanan" origin; cf. e.g. the "old"
species _D.arcturi_, _D.stenopetala_ or the subantarctic range of
_D.uniflora_; keep in mind that AU started to migrate from the S temperate
zone! The relict _D.meristocaulis_ is confined to high altitudes on the
Neblina, which has a more "temperate" climate than the surrounding rain
forest) has led to numerous (new) adaptations, hybridization, etc., and
some of the recent SW AU/S AF taxa of _D._ are quite certainly young
(originally mediterranean) elements, or neoendemics.

The zones of mediterranean climate are well known for a high degree of
endemism (hot spots of adaptive radiation, refuges for relicts, "melting
pots" of more temperate and more tropical elements). The special geography
and history of S AM has *not* led to (or forced) establishment of _Drosera_
in the (now) mediterranean zone (C Chile) => the observed ## and
distribution of endemic species in AU, AF, and AM.

Kind regards