Re: Miscellaneous (none off-topic)

From: SCHLAUER@chemie.uni-wuerzburg.de
Date: Wed Feb 24 1999 - 14:19:09 PST


Date:          Wed, 24 Feb 1999 14:19:09 
From: SCHLAUER@chemie.uni-wuerzburg.de
To: cp@opus.hpl.hp.com
Message-Id: <aabcdefg564$foo@default>
Subject:       Re: Miscellaneous (none off-topic)

Dear Nigel & al.,

> Equal ploidy doesn't guarantee fertility in a hybrid

But if the parents are of equal ploidy, the chances for fertile
offspring are greater (at least in _Drosera_).

> Both parents of 'Lake Badgerup' set seed unaided,

This is no convincing proof for equal ploidy. So far, the numbers 6,
7(!), 8, 10, 12, 14, 18, 28, and 64 (plus "20-22" and "28-34") have
been reported for subgen. Bryastrum alone. BTW: If they are able to
form a viable hybrid (whether sterile or not but at least existing),
I would expect both parents to be rather fertile.

> whereas I have
> never managed to get seed from the hybrid even with a bit of help.

This would not be too surprising if _D. occidentalis_ had a chromosome
count different from 28, which is (v.s.) not entirely unlikely.
Anyway, we need a count for the _D. occidentalis_ parent (a plant
from the type locality of the hybrid!) of _D. *badgerupii_.
Otherwise, any discussion of the topic is of limited value.

> Martin Zevenbergen, did you do a chromosome count on D occidentalis?
> It wasn't in the list you sent me.

Is this list available somewhere? Where?

> Jan, is Drosera citrina fertile? My plants are on loan to a
> photographer to have their flowers photographed, but when they come
> back I will get my paintbrush out .

I am not sure. There were seeds (unfortunately, I do not recall the
source) labeled "D. rechingeri" (the species Allen Lowrie confused
with _D. citrina_ before 1992, and the only name under which he and
others sold _D. citrina_ until that date; the true _D. rechingeri_
was exclusively available under the bogus name "Coolamon"). I took
these for seeds of _D. citrina_ in my description of D. chrysochila
(a few-days-later synonym of _D. citrina_). In his discussion of this
species in CPN, Martin Cheek (Hi, Martin!) mentioned that _D. citrina_
was sterile. So I am no longer convinced the seeds were identified
correctly (they never germinated).

Kind regards
Jan



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