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Howdy,
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I would also add that there is probably no REAL evidence that these plants are not species. Peter may have evidence against my arguments below. (If so, I hope he tells me). First off, they may be extinct in wild, or just not yet found in the wild.
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Secondly, their natural habitat may have been the same natural habitat for human habitation. For example in California, there are fairy shrimp species found nearly always where there is human habitation. However, human habitation and the seasonal wetlands the shrimp live in both occur on flat ground, above the flood areas. Also the human habitation has spread so very much, that it is nearly impossible to find flat land above the flood zones that does not have Humans.
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Thirdly, these may be plants that adapted to human habitation areas naturally, due to their ability to handle certain levels of disturbance.
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So, speaking as a professional taxonomist who runs into these amazing puzzles from time to time, there are often many explanations to taxonomic and evolutionary problems. Plus, I think the only real difference between a cultivar and a species is natural selection verses artificial selection.
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Happy days,
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Christopher
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Tony:
While we certainly like neat packages, those of us working in mega-rich
places are under no illusions that the species often haven't read the same
rule books!
Certainly 'species' such as A. macrorrizos and A. cucullata bend the
boundaries a lot. What is of course interesting is that A. macrorrhizos
(notwithstanding its doubtful 'pure' species status) is definitely related
(and here we are talking molecularly) to some unquestionably 'good' species,
such as A. portei and A. flabellifer, which poses even more difficulties. It
is also problematic to lalk about utilization of cultivars, especially those
that are selections of what may themselves be cultivars, albeit so
long-standing that they have effectively stabilized and function as species,
even to the extent that they have lost the ability to hybridize with other
elements of what was once a single gene pool.
Forgive me if I appear to be avoiding answering your suggestion. But the
fact is that I am not sure HOW to answer. The bottom line is that, at
present, we can only be sure that A. macrorrhizos and A. cucculata are NEVER
found away from human disturbance in 'habitat' and furthermore, away from
the attention of horticulturists are remarkable morphologically stable.
As a final thought on this, it is also important to remember that species
framework, and the interspecific crossing is often in nature not just a
matter of 'incompatibility'. Distribution, flowering time even down to the
level of time of day, and how these barriers function to manage
pollinators, or select for a particular pollinator guild, are as much, if
not more, a barrier than simple unrelatedness. If ever an example was needed
of the role of pollinator guild niche selection, the orchids of the
Stanhopineae contain numerous examples.
Cheers
Pete
-----Original Message-----
From: aroid-l-bounces@gizmoworks.com [mailto:aroid-l-bounces@gizmoworks.com]
On Behalf Of Tony Avent
Sent: 05 September 2009 21:29
To: Discussion of aroids
Subject: Re: [Aroid-l] Alocasia of Thailand
Pete:
I thought it was botanists/taxonomists who like nice neat nomenclatural
packages. These cultons sound instead like a botanical grab bag into
which all of the unsorted material is dumped. If they are indeed
selections of A. odora, then they certainly need cultivar names with A.
odora as a species. If, as Lari Ann suggests, they are cultivars which
cannot be assigned to a particular species, but are old hybrid groups or
species whose origins have been obscured, they still need a cultivar
name. Newly selected clones from them would then also need cultivar
names. This actually would make these fit much better into neat
nomenclatural packages. We would then know which new cultivar came from
which old cultivar of say, A. macrorrhizos. I tend to like the analysis
from plant breeders and can attest that outside of DNA, this is one of
the best ways to tell what is related to what. That being said, has
anyone done DNA analysis on this group?
Peter Boyce wrote:
> Tony:
>
> The x would indicate that they are stabilized hybrid species
(nothospecies)
> as, for example, the situation with Cryptocoryne x purpurea (a
nothospecies
> resulting from the stabilization of the naturally occurring hybrid C.
> cordata x C. griffithii) this is not the case. Alistair and are both
pretty
> much convinced that A. cucullata and A. macrorrhizos are stabilied
cultigens
> (cultons) of A. odora. In cultivation thus they COULD be cited a A.
> 'Macrorrhizos' and A. 'Cucullata', but that would then lead to problems
with
> cultons of these. Best to leave the situation as is.
>
> Cheers
>
> Pete
>
> -----Original Message-----
> From: aroid-l-bounces@gizmoworks.com
[mailto:aroid-l-bounces@gizmoworks.com]
> On Behalf Of Tony Avent
> Sent: 05 September 2009 00:45
> To: Discussion of aroids
> Subject: Re: [Aroid-l] Alocasia of Thailand
>
> Pete:
>
> I was just reading over your fascinating paper on Alocasia in Thailand
> about both Alocasia cucullata and A. macrorrhizos not being valid
> species. If this is the case and they are old cultigens, why would
> they not be properly written a Alocasia x macrorrhizos and Alocasia x
> cucullata with an appropriate cultivar name for the clone in commerce?
>
> Peter Boyce wrote:
>
>> Dear All,
>>
>>
>>
>> For anyone interested there is attached to this a recent paper on the
>> /Alocasia/ in Thailand, including the description of a large-growing
>> species from the Thai/Cambodian border.
>>
>>
>>
>> Peter
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> Aroid-L mailing list
>> Aroid-L@www.gizmoworks.com
>> http://www.gizmoworks.com/mailman/listinfo/aroid-l
>>
>
>
--
Tony Avent
Plant Delights Nursery @
Juniper Level Botanic Garden
9241 Sauls Road
Raleigh, North Carolina 27603 USA
Minimum Winter Temps 0-5 F
Maximum Summer Temps 95-105F
USDA Hardiness Zone 7b
email tony@plantdelights.com
website http://www.plantdelights.com
phone 919 772-4794
fax 919 772-4752
"I consider every plant hardy until I have killed it myself...at least three
times" - Avent
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