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hardy  Aroids)" <ARISAEMA-L at NIC.SURFNET.NL> Aroids)" <ARISAEMA-L at NIC.SURFNET.NL>
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From: "J.E. Shields" <jshields104 at INSIGHTBB.COM>
Subject: Re: More on conservation, and associated matters, hybridiza=
tion,  genomes, etc
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Adam and all,

For some reason, my e-mail software sent only the preliminary version of
the message from me just now.  Here is what should have done out as the
final text:

Disclaimer: I was trained as a chemist and biochemist; my knowledge of
genetics, plant breeding, or taxonomy, is only that of an earnest amateur.

Many plant species are self-incompatible, presumably to prevent excessive
inbreeding and possible weakening by accumulation of deleterious recessiv=e
gene alleles.  As I understand most definitions of "species" they refer t=o
populations which can interbreed freely.  "Population" is as important as
"interbreed" in the definition.

Self Incompatibility occurs in many species of the Amaryllidaceae as well
as in other plant families.  Physiologically, it takes a number of
different forms at the biochemical level, always involving something that
blocks the fertilization of an ovule by the incompatible pollen.  Some
forms of incompatibility involve stopping the growth of the pollen tube
down the style; other forms may prevent germination of the pollen grain o=n
the stigma.  There are others mechanisms too, but I don't recall any
details at the moment.

To preserve the genes of a rare, vanishing species, hybridization offends
purists but is the only avenue open when only a single fertile individual
is available.  It is, I agree, highly undesirable; even less desirable is
the complete disappearance of the entire genome of a species.

I didn't notice that anyone responded to my remarks about record
keeping.  Doesn't anyone other than Pascal and me keep records of their
plant collections?  If you do, I'd be interesting in hearing how you go
about it.  Pascal, have you any suggestions for amateur plant collectors =on
how to proceed with keeping records?

-From the MOBOT database, it appears that A. amurense is tetraploid while
A. triphyllum is diploid.  That is not surprising; speciation by polyploi=dy
is not unknown in the plant world.

Adam, I note that you live in Chicago.  I am in Westfield, Indiana, about
25 miles north of downtown Indianapolis.   If you -- or any other members
of Arisaema-L -- are ever down this way, please get in touch with me.  I
enjoy visits from other plant enthusiasts.  We have an acre of daylilies
(hybrids) that reach peak bloom in the first two weeks of July.  I have t=wo
home greenhouses, one of which is half filled with Clivia.  The Clivia ar=e
just starting to bloom now.  In the same greenhouse, Hippeastrum
("amaryllis") are starting to bloom now, too.  In the other greenhouse,
Cyclamen are still blooming, and Lachenalia are almost over.  One Scadoxu=s
puniceus bloomed this year, and its flower is starting to fade.

Jim Shields
in central Indiana

Glossary:

I don't want to insult those who already know the technical terms I use,
but maybe not everyone does.

allele -- one of a number of different forms of a given gene
speciation -- formation of new species from an old species

At 11:32 PM 3/9/02 -0600, you wrote:
I see that I have touched on some sore points.  Let me tell you some of
these points ae sore with me too!  ABout 30-35 years ago I was instrument=al
in importing rare oncocyclus iris species that had not been in the countr=y
for more than 25 years.  They were distributed among those who knew best =how
to grow them., and those who were willing to pay in an enthusiast group n=ot
unlike this  onbe but I don';t really now anyone here.  I assume that all=of
you who have rare species know how to grow them and never lose them
?  )<G>?  At any rate. Many of these were hybridized.  They do not self
readily, at all.  (Most plants have barriers to self-pollination)  And mo=st
of what we are pleased to call "species"  are artificial entities
established by people (not given by God, or something)  based on holotype=s
which are dried specimens in  an herbarium   (which in the case of irises
may not exist any more, neither the herbarium or the holotype).  Some of
these irises exist (as far as is known) only in their hybrids,
unfortunately.,because their original provenance has been over-collected =and
the limited colonies are gone.  Others exist in profusion, but some forms
are gone., others, as I noted are subject to the inroads of increased
building, etc.

I do not necessarily recommend hybridization as a primary way of maintain=ing
any species--but, do these things self-pollinate?  and set viable seed?  =So
far the hints I've gotten are that they may, or may not.   How does a
species maintain its identity and euploid genome and supposed uniqueness =,
if it cannot set seed from self-pollination?  I don't have a good answer =to
this, and suspect I won't because our conceptualization of what goes on
isn't a sufficient tool to answer this. .  Irises set seed within colonie=s
of a species, where (one may assume) the individuals are sufficiently
distinct and different enough to not trigger the enzymes that would block
fertilization, and certainly there is variation within a speciecs.  But,
people decide  whether the variation within the colony is so great as to
remove it from a species classification, and assign it a forma, or a var.
or,  an aff.  or   remove it from the species, or even  the genus,.  This=is
what keeps taxonomists busy, but I'm not going to say that what's good fo=r
taxonomists (or General Motors) is good   for conservation or the world..

Just in my lifetime, a number of species have become extinct. I note this=,
even as I shall become extinct, and even as some of my children have.  Re
hybridization:I don't think I suggested that indiscriminate hybridization
was a goal or a likelihood.  With the chromosome numbers noted so far, I
suspect that hybridization may be more dificult than  imagined

Do we even have agreement on how to grow these things?   Do members of th=is
group grow them reliably?  year in and year out?  I salute the idea of th=e
exchange program and the entering requirement for AEG of who has what and
where .    Has each of you made arrangements about what should be done wi=th
your collection in case of your death?    Just this last few weeks I was
lucky enough to brng a few rare hybrids from Australia into the US.  Some=no
longer existed in the U.S., others were developed in Australia and never
entered commerce here.   At this time there is one rhizome of each of
hybrid  of a "species" for which the provenance has never been establishe=d

I should note , also, that the hybridization of oncocyclus and regelia
irises has been in large measure the result of backyard gardeners who hav=e
taken the trouble to learn the requisite skills to raise the seed
(notoriously difficult to germinate in the past, short of embryo culturin=g
it).  Very few people in the U.S. have been able to keep the oncocyclus
species alive for more than a few years at a time  I suspect that some of
the arisaemas may prove equally fractious,  but I hope not.

I don't know how to grow these things in Chicago, yet., except for
triphyllum and dracontium which are native in the area.  But I hope to
learn.    In evolutionary terms, I would not be surprised to find that A.
triphyllum and amurense are exceedingly close, even as skunk cabbage here
and in Siberia probably are.  Thanks to all who decided to respond.  I
printed out the information on registration of cultivars which was new to
me.

Adam Fikso,  3620 Glenview Rd., Glenview, IL 60025 USDA  Zone 5a,  to -=25F



*************************************************
Jim Shields             USDA Zone 5             Shields Gardens, Ltd.
P.O. Box 92              WWW:    http://www.shieldsgardens.com/
Westfield, Indiana 46074, USA                   Tel. +1-317-896-3925