While I don't know any larches personally, I occasionally have to label them
for a bonsai show, so this has me puzzled. The usually accepted name for
Dunkeld larch is Larix xleptolepis, which dates from 1919. Larix xmarschlinsii,
dating from 1917, is on the RHS checklist of accepted names of conifer species
(for registration of cultivars). However, IPNI only lists L. xeurolepis,
opening the question of whether xmarschlinsii was validly published. And
W3TROPICOS lists neither of them, although it lists several other larch
hybrids.
Can anyone throw further light on this?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"The trouble with people is not that they don't know but that they know so much
that ain't so."
Josh Billings (Henry Wheeler Shaw), 1818-1885

The usually accepted name for Dunkeld larch is Larix xleptolepis,
Oops. I meant Larix xeurolepis. L. leptolepis is the old name for L. kaempferi,
one of the parents.
A quick Web search shows that Dunkeld larch still goes by both names. A history
of the tree is a bit cloudy. The Japanese larch was introduced to the Atholl
Estates, & the Dunkeld larch subsequently developed & was planted there. So is
it a true natural hybrid altogether?


Iris,
Central NY, Zone 5a, Sunset Zone 40
"The trouble with people is not that they don't know but that they know so much
that ain't so."
Josh Billings (Henry Wheeler Shaw), 1818-1885

While I don't know any larches personally, I occasionally have to label
them for a bonsai show, so this has me puzzled. The usually accepted name
for Dunkeld larch is Larix xeurolepis, which dates from 1919. Larix
xmarschlinsii, dating from 1917, is on the RHS checklist of accepted names
of conifer species (for registration of cultivars). However, IPNI only lists
L. xeurolepis, opening the question of whether xmarschlinsii was validly
published. And W3TROPICOS lists neither of them, although it lists several
other larch hybrids.
Can anyone throw further light on this?

+ + +
Some notes:
- the RHS list accepts Larix xmarschlinsii
- so does Mabberley, starting in 1987
- W3TROPICOS list four hybrids, but at least three of them are 'natural
hybrids' occurring in the wild. Maybe the fourth is one too. And Tropicos
may list only 'wild taxa'???
- The fact that IPNI does not list Larix xmarschlinsii does not mean
anything except that it does not list it. Listing by IPNI is not a
requirement for valid publication (it was proposed that all new names are
required to be submitted to a registering society, which would certainly
make life easier for anybody looking for a name. It was sunk without a trace
in 1999 at StLouis). Although IPNI is the best we have got, there are quite
a few names not lited by IPNI.

I am still going for the 1980 publication. Of course if this 1980
publication were to happen today a proposal to conserve Larix xeurolepis
would be the thing to do. In 1980 this was not yet possible.
+ + +

A quick Web search shows that Dunkeld larch still goes by both names. A
history of the tree is a bit cloudy. The Japanese larch was introduced to
the Atholl Estates, & the Dunkeld larch subsequently developed & was planted
there. So is it a true natural hybrid altogether?
Iris,

+ + +
Since the two species do not naturally meet it is not a natural hybrid!
PvR

And Tropicos may list only 'wild taxa'?
Probably.

Although IPNI is the best we have got, there are quite a few names not
listed by IPNI.
I thought IPNI is supposed to include everything in IK.

Of course if this 1980 publication were to happen today a proposal to
conserve Larix xeurolepis would be the thing to do
Why?

Since the two species do not naturally meet it is not a natural hybrid!
That explains it. So what do you call the name Larix xmarschlinsii?


Iris,
Central NY, Zone 5a, Sunset Zone 40
"The trouble with people is not that they don't know but that they know so much
that ain't so."
Josh Billings (Henry Wheeler Shaw), 1818-1885

And Tropicos may list only 'wild taxa'?

Iris Cohen schreef
Probably.

Although IPNI is the best we have got, there are quite a few names not
listed by IPNI.
I thought IPNI is supposed to include everything in IK.

+ + +
IPNI does include everything in the IK, as well as from some other indexes.
However the IK is far from complete. For the regular heavy user it is not at
all uncommon to find something that is not in the IK
+ + +

Of course if this 1980 publication were to happen today a proposal to
conserve Larix xeurolepis would be the thing to do
Why?

+ + +
There are a lot of people fed up with name changes for nomenclatural
reasons. There was so much pressure that in 1988 even the Americans
relented, and it became possible to conserve names of species.
Since Larix x eurolepis is a name of a taxon of considerable economic
importance it would have been a shoo-in to be conserved.
+ + +

Since the two species do not naturally meet it is not a natural hybrid!

That explains it. So what do you call the name Larix xmarschlinsii?
Iris
+ + +
The name of a hybrid?
PvR

In article , Iris Cohen
writes
However, IPNI only lists L. xeurolepis,
opening the question of whether xmarschlinsii was validly published.

IPNI is not complete. (For example the French flora at INRA has many
synonyms not in IPNI, and I've found other additional synonyms from a
variety of sources.)

Stace (New Flora of the British Isles, 1st edn.) uses _L. x
marschlinsii_. If I interpret his text correctly _L. x eurolepsis_ was
*not* validly published.
--
Stewart Robert Hinsley

In article , Iris Cohen
writes
That explains it. So what do you call the name Larix xmarschlinsii?

The name of a notho- (i.e. hybrid) taxon, more specificially of a hybrid
arising spontaneously in cultivation.
--
Stewart Robert Hinsley

The name of a notho- (i.e. hybrid) taxon, more specificially of a hybrid
arising spontaneously in cultivation.

If two species form a hybrid, with certain characteristics, and then in a
completely different locale, the same two species independently form a hybrid,
with different characteristics, are the two different hybrid forms the same
species?

Jie-san Laushi

Huodau lau, xuedau lau, hai you sanfen xue bulai
_____________________________________________
to email: eliminate redundancy

In article , Jie-san
Laushi writes

If two species form a hybrid, with certain characteristics, and then in a
completely different locale, the same two species independently form a hybrid,
with different characteristics, are the two different hybrid forms the same
species?

By definition, all hybrids between two species belong to the same
nothospecies (hybrid). However if speciation by hybridisation is added
to the mix, then it becomes a matter for determination by observation
(and argument over species definitions).
--
Stewart Robert Hinsley

Jie-san Laushi writes
If two species form a hybrid, with certain characteristics, and then in a
completely different locale, the same two species independently form a
hybrid, with different characteristics, are the two different hybrid forms
the same species?

Stewart Robert Hinsley schreef
By definition, all hybrids between two species belong to the same
nothospecies (hybrid). However if speciation by hybridisation is added
to the mix, then it becomes a matter for determination by observation
(and argument over species definitions).
--
Stewart Robert Hinsley

+ + +
To put it a little differently (this also came up a month or so ago)

If the result of hybridization between two taxa is given the status of a
nothotaxon then all the hybrids, no matter what their characters belong to
that nothotaxon. The well-known example is Magnolia x soulangeana which
contains quite a number of cultivars of varying appearances.

The result of hybridization need not be given the status of a nothotaxon,
but can be recognised as a regular taxon, for example a species. In that
case the delimitation of this species is a matter of taxonomic judgement.
It is conceivable that species A and species B hybridize at the
southern-most point of their range and that the result becomes species C. If
beside that species A and species B hybridize at the northern-most point of
their range the result may be different enough to become species D. I would
not know of a real-life example, but it is conceivable.
PvR

In article , P van Rijckevorsel
writes
It is conceivable that species A and species B hybridize at the
southern-most point of their range and that the result becomes species C. If
beside that species A and species B hybridize at the northern-most point of
their range the result may be different enough to become species D. I would
not know of a real-life example, but it is conceivable.

Found one (not geographical)

Species A : Cardamine amara
Species B : Cardamine rivularis
Species C : Cardamine insueta
Species D : Cardamine schulzii

Cc. amara and rivularis are diploids. C. insueta is a sexually
reproducing permanent odd polyploid (triploid, RRA), similar to Rosa
canina. C. schulzii is a hexaploid (RRRAAA).

Source: Verne Grant, Plant Speciation, 2nd edn, pp. 409-410.
--
Stewart Robert Hinsley

P van Rijckevorsel writes
It is conceivable that species A and species B hybridize at the
southern-most point of their range and that the result becomes species C. If
beside that species A and species B hybridize at the northern-most point of
their range the result may be different enough to become species D. I would
not know of a real-life example, but it is conceivable.

Stewart Robert Hinsley schreef in berichtnieuws
...
Found one (not geographical)

Species A : Cardamine amara
Species B : Cardamine rivularis
Species C : Cardamine insueta
Species D : Cardamine schulzii

C. amara and rivularis are diploids. C. insueta is a sexually
reproducing permanent odd polyploid (triploid, RRA), similar to Rosa
canina. C. schulzii is a hexaploid (RRRAAA).

Source: Verne Grant, Plant Speciation, 2nd edn, pp. 409-410.
--
Stewart Robert Hinsley

+ + +
Great!
Polyploids have their own mechanisms of sexual isolation come.

However I expect it will be a lot harder to find a set of four diploid
species. This almost surely will require a geographical component. In
addition, with today's tradition of lumping most taxonomists would say "four
populations of plants that are interbreeding? Must be one species"
PvR

In article , P van Rijckevorsel
writes
Great!
Polyploids have their own mechanisms of sexual isolation come.

However I expect it will be a lot harder to find a set of four diploid
species. This almost surely will require a geographical component.

Perhaps in Azolla

Azolla caroliniana
Azolla filiculoides
Azolla microphylla
Azolla mexicana

http://www.botany2002.org/section11/abstracts/4.shtml
http://www.jaknouse.athens.oh.us/ferns/g_azol.html

It's not clear whether Aa. microphylla and mexicana represent one or two
hybridisation events. (Or even zero, depending on whether you accept the
position given in the first link,)
In
addition, with today's tradition of lumping most taxonomists would say
"four populations of plants that are interbreeding? Must be one
species"
PvR

Not always; at least I don't think anyone has proposed sinking the white
oak syngameon into a single species (Quercus robur?). More particularly,
Q. robur and Q. petraea are still recognised, as are Betula pendula and
Betula pubescens, even tho' both pairs of species hybridise extensively.
Similarly in Salix.
--
Stewart Robert Hinsley

So what do you call the name Larix xmarschlinsii?
The name of a notho- (i.e. hybrid) taxon, more specificially of a hybrid
arising spontaneously in cultivation.

So it is the same as xFatshedera lizei.
Now where do we put xCitrofortunella mitis (Calamondin)? Is there some location
where the natural habitats of tangerines & kumquats overlap, or did it arise in
cultivation in the distant past?
One of the interesting aspects of hybridizing, at least in orchids, is that
occasionally there is a registered artificial hybrid which is subsequently
discovered to be also a natural hybrid. The latter is published by a botanical
taxonomist, following which the poor plant is doomed forever to carry two
different names. According to RHS rules. If it is used as a parent in
hybridizing, it is called by the registered name. If the natural hybrid
discovery comes first, the plant only has one name, but it may be written
differently or carry a Latin ending.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"The trouble with people is not that they don't know but that they know so much
that ain't so."
Josh Billings (Henry Wheeler Shaw), 1818-1885

P van Rijckevorsel writes
However I expect it will be a lot harder to find a set of four diploid
species. This almost surely will require a geographical component.

Stewart Robert Hinsley schreef
Perhaps in Azolla

Azolla caroliniana
Azolla filiculoides
Azolla microphylla
Azolla mexicana

http://www.botany2002.org/section11/abstracts/4.shtml
http://www.jaknouse.athens.oh.us/ferns/g_azol.html

It's not clear whether Aa. microphylla and mexicana represent one or two
hybridisation events. (Or even zero, depending on whether you accept the
position given in the first link,)

+ + +
I am not much on ferns, but I don't see anything on hybrids in these links?

In addition, with today's tradition of lumping most taxonomists would say
"four populations of plants that are interbreeding? Must be one
species"
PvR

========
Not always; at least I don't think anyone has proposed sinking the white
oak syngameon into a single species (Quercus robur?). More particularly, Q.
robur and Q. petraea are still recognised, as are Betula pendula and Betula
pubescens, even tho' both pairs of species hybridise extensively.
Similarly in Salix.
--
Stewart Robert Hinsley

+ + +
I know next to nothing about Smilax, but the taxonomy of Betula is only just
short of a regular nightmare.
PvR