Re: Re: S. leucophylla, Catopsis b., et al.

Date: Wed May 26 1999 - 09:10:41 PDT

Date:          Wed, 26 May 1999 09:10:41 
Message-Id: <aabcdefg1841$foo@default>
Subject:       Re: Re: S. leucophylla, Catopsis b., et al.

Dear Dave et al.,

> And we ought to be able to tell if they have close relatives
> that aren't CP's anymore by looking at their flowers. I have
> never heard of any such thing.

The weird thing is that it seems (from genetical analyses, not from a
similarity of flower structures) that _Roridula_ (ever heard this
name? ;-)) is the genus most closely related to Sarraceniaceae. Even
phytochemical analyses do indicate an affinity of both groups. These
two together constitute an isolated group in Ericidae, the subclass
that also contains the orders Ericales (heaths, rhododendrons),
Primulales (primroses) and others.

In all cases of cps I know of, carnivory seems to be the final
(most recent) stage of an evolutionary process rather than an early,
ancestral one. Representatives of non-carnivorous relatives of cp
families are extant in most groups containing cps:

  cps: Lentibulariaceae, Byblidaceae
  non-cps: Orobanchaceae, Scrophulariaceae, Gesneriaceae, Labiatae,

Ericales (
  cps (or sub-cps): Sarraceniaceae, Roridulaceae
  non-cps: Ericaceae, Actinidiaceae

  cps: Droseraceae, Drosophyllaceae, Dioncophyllaceae (p.p.),
  non-cps: Dioncophyllaceae (p.p.), Ancistrocladaceae,
           Plumbaginaceae, Polygonaceae

The exception is _Cephalotus_. With the genetical data available (two
genes sequenced) producing confusing and highly contradictory clues,
no clear affinity can be proposed on a convincing basis.

Kind regards

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