Lilium 'Mrs R O Backhouse'

Jim McKenney
Sun, 03 Jun 2007 11:13:27 PDT
Kenneth Hixon wrote: “x dalhansonii is a grex name for all the seedlings of
the cross of 
L. martagon dalmaticum
and L. hansonii, and they do of course vary to some extent.  How long 
seedlings of the
seedlings of the original cross are entitled to the x dalhansonii name, 
I am unsure,”

I find that statement confusing, and perhaps I misunderstand what Ken means.

To begin with, does the term grex have any official status in reference to
lilies? I’m not aware that it does. In my experience, lily growers have used
the term, probably incorrectly, to describe those situations where tissue
culture has yielded several very similar cultivars from a given cross. In
the cases I have in mind, it has never been determined if the cultivars in
question are actually separate clones or simply the result of a single clone
splitting up very early in the tissue culture process.

I've read that Jan de Graaff selected particularly fine examples of, for
instance, his trumpet hybrids and used these particular plants repeatedly in
certain crossing combinations as parents in his hybridization work. That
usage is close to breeding greges, although as far as I know the public was
never aware of the specific parents of such crosses, and de Graaff's
commercial offerings were not offered as greges but rather as true breeding
strains (these strains being made up presumably of several or many
unspecified and very similar greges).  

On the other hand, for purposes of discussion, let’s assume grex is properly
used with lilies. The progeny of a cross having the parents  specified in
the naming of the grex   would be entitled to the grex name forever – or at
least as long as the term grex is used in its current meaning. 

However, and this is where Ken’s original post confused me, he seemed to be
saying that crosses of Lilium × dalhansonii  inter se – i.e.  [Lilium ×
dalhansonii]   ×  [L. × dalhansonii] are also properly assigned to the grex
called Lilium × dalhansonii.  

Shouldn’t such a cross have a different grex name (because such a cross does
not have the parents specified in the original grex)?

Jim McKenney
Montgomery County, Maryland, USA, USDA zone 7, where Lilium hansonii and L.
candidium are blooming.
My Virtual Maryland Garden
Webmaster Potomac Valley Chapter, NARGS 
Editor PVC Bulletin 
Webmaster Potomac Lily Society

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