Dwarf Tulipa - catching up

J.E. Shields jshields104@insightbb.com
Wed, 25 Feb 2004 15:10:44 PST
Lest Jim McK. feel that no one is reading what he writes, I would like to 
take issue with him on a couple of minor points.

Hemerocallis fulva is a perfectly good diploid, fertile species.  H. fulva 
'Europa' is the almost sterile triploid.

As I recall, Verne Grant in his book on plant speciation (the exact title 
of which I've forgotten) discussed parthenogenic races of known sexual 
species in the rain lilies (I think it was) as reproductively isolated and 
hence separate or at least emerging new species.  If a triploid race is 
truly reproductively isolated, it could slowly drift away from its genetic 
identity with the ancestral sexually reproducing population until it really 
became a new species.

At any rate it is an interesting phenomenon, no matter how you want to 
treat the plants.

Jim Shields
in central Indiana

At 03:34 PM 2/25/2004 -0500, you wrote:
>In discussing Tulipa saxatilis and Tulipa bakeri Lilac Wonder, Mark
>McDonough said:
> >The two species are regarded as quite distinct...
>And he is quite right. But regarded so by whom, and why? As garden plants
>they certainly are distinct. But are they "two species"? That's where it
>gets interesting. And if you read on, perhaps you will emerge with a
>different opinion. A brief layperson's glossary is provided at the end to
>help keep everyone up to speed in this discussion.
>The name Tulipa saxatilis was originally used for a triploid tulip.
>Triploids do not form sexually reproducing populations. They cannot be true
>species; there has to be more to the picture.
>Tulipa cretica and Tulipa bakeri are the likely candidates for
>consideration as the source of T. saxatilis. For purposes of discussion,
>let's assume that it was T. bakeri. T. bakeri was named later than T.
>saxatilis. That means that if T. saxatilis is regarded as a triploid form
>of T. bakeri, the name for the aggregate becomes T. saxatilis. It's a case
>of the rules of nomenclature requiring that the tail (triploid, nominal
>species Tulipa saxatilis) wag the dog (diploid sexually reproducing species
>T. bakeri).
>If evidence should arise showing that T. saxatilis has some other origin,
>then the entire picture changes.
>For those of you who do not have a technical background yet want to
>understand what this is all about, here are some informal definitions:
>diploid: with two sets of chromosomes, one from each parent
>triploid: with an extra set of chromosomes. The term "sterile triploid" is
>virtually a cliche, but it is an inaccurate one; triploids can and do set
>viable seed under the right conditions.
>sexually reproducing populations: for purposes of this discussion, true
>nominal species: species in name only, not really true species; in the bad
>old days, taxonomists named everything in sight before they really knew
>enough about the biology of the entity in question. Familiar examples of
>nominal species are Lycoris squamigera, Lilium lancifolium, Hemerocallis
>fulva and Crocus sativus.
>Jim McKenney
>Montgomery County, Maryland zone 7 where foliage of Tulipa saxatilis
>planted in early December is just emerging.
>pbs mailing list

Jim Shields             USDA Zone 5             Shields Gardens, Ltd.
P.O. Box 92              WWW:    http://www.shieldsgardens.com/
Westfield, Indiana 46074, USA
Tel. ++1-317-867-3344     or      toll-free 1-866-449-3344 in USA

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