Date: Mon, 8 May 2000 20:50:12 +0000 From: schlauer@chemie.uni-wuerzburg.de To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1439$foo@default> Subject: re: Oldest CP
Dear Ivan,
> I can't tell you what the oldest now living species of CP is, but I think
> we would all agree that the most primitive or simple CP is a bromiliad
> such as Brochinia or Catopsis.
Bromeliads are probably a young family (almost restricted to S
America, the epiphytic habit is a derived condition). Only the
monocot/dicot division is old, but bromeliads are not very close to
this basal branch.
> I think probably the oldest family of CP
> is the butterwort family ( butterworts, Genlisea, Utricularia ) since
> they are the most diverse.
This is certainly not the case (neither are they the oldest family,
nor are they the most diverse - above the rank of species). As a
Scrophularialean (Asterid) family, they belong to the youngest branch
of dicots, and they can simply not be older than the group including
them. The diversity (above species level) of Droseraceae is much
greater than in Lentibulariaceae. The traps are never of a primitive
type in Lentibulariaceae, and even _Pinguicula_ has much more
specialized glands than e.g. _Drosophyllum_. The most obvious
advanced condition in Droseraceae is the motility of leaves or
tentacles, but similar (only somewhat slower) movements can be
observed in _Pinguicula_. The flowers of Lentibulariaceae are both
extremely specialized and morphologically very homogeneous throughout
the family.
> The sundew family in which some include
> Aldrovanda is also very diverse, but not quite so much.
In Droseraceae there are more pollen types, more variation in numer
of flower parts and style morphology. The actinomorphic flower type
is less specialized than the zygomorphic, sympetalous type of
Lentibulariaceae. In the fossil record (that reaches further back
than in Lentibulariaceae) there are even more genera than in
Lentibulariaceae. All this indicates a much earlier origin of
Droseraceae (together with its Caryophyllid ancestors that are all
older than the Asteridae). The lower diversity of Droseraceae at
specific rank can be explained by the very prolific but rather recent
(Late Tertiary) radiation of _Utricularia_ and _Pinguicula_ and by
massive extinctions of whole genera of Droseraceae in the Tertiary..
> The most simple
> of the butterwort family are the butterworts. I don't believe these were
> around during the dinosaur reign.
Certainly not. Lentibulariaceae and their allies begin to appear in
the Tertiary (too late for the last dinosaur).
> In
> conclusion, we can not appreciate our carnivorous plants for the same
> reason as your dinosaur aged plants.
_Aldrovanda_ is (close to) a dinosaur aged plant.
Kind regards
Jan
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