does anyone know the origin of this cultivar? Is it a variety of B. pendula or
not?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

The Oregon Nursery Guide (www.nurseryguide.com) lists it as Betula alba a synonym
of B. pendula according to other sources. The Amer. Hort. Soc. Encyclopedia dodges
the question by giving it a listing separate from all species. Not much help I'm
afraid.

Gene Newcomb

Iris Cohen wrote:

does anyone know the origin of this cultivar? Is it a variety of B. pendula or
not?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

In article , Gene Newcomb
writes
The Oregon Nursery Guide (www.nurseryguide.com) lists it as Betula alba a
synonym
of B. pendula according to other sources. The Amer. Hort. Soc. Encyclopedia
dodges
the question by giving it a listing separate from all species. Not much help I'm
afraid.

The RHS Plantfinder also doesn't assign it to a species, but it does
come up on a search for Betula pendula.

URL:http://www.rhs.org.uk/rhsplantfinder...?crit=Betula%2
0and%20Trost&Genus=Betula

URL:http://www.rhs.org.uk/rhsplantfinder...?crit=Betula%2
0and%20pendula&Genus=Betula

IIRC, Betula alba included both Betula pendula and Betula pubescens

Govaerts, R. 1996. (1261) Proposal to reject the name _Betula alba_
(Betulaceae) Taxon 45: 697-8, may clarify this.
--
Stewart Robert Hinsley

The name Betula alba is a good marker for an obsolete book or site.
These days it even is a rejected name (a genuine one).
PvR


Gene Newcomb schreef
The Oregon Nursery Guide (www.nurseryguide.com) lists it as Betula alba a
synonym of B. pendula according to other sources. The Amer. Hort. Soc.
Encyclopedia dodges the question by giving it a listing separate from all
species. Not much help I'm afraid.

Gene Newcomb

===============
Iris Cohen wrote:

does anyone know the origin of this cultivar? Is it a variety of B.
pendula or not?
Iris,

The name Betula alba is a good marker for an obsolete book or site.

I realize that the correct name is B. pendula, but that doesn't help. Some
authorities list 'Trost's Dwarf' as a cultivar of B. pendula, others simply as
a Betula cultivar. According to the botanist at Hillier Gardens, 'Trost's
Dwarf' has downy shoots, which makes him think it is not B. pendula. They don't
have the plant any more, so he has no further information.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

The name Betula alba is a good marker for an obsolete book or site.

Iris Cohen schreef
I realize that the correct name is B. pendula, but that doesn't help. Some
authorities list 'Trost's Dwarf' as a cultivar of B. pendula, others simply
as a Betula cultivar. According to the botanist at Hillier Gardens, 'Trost's
Dwarf' has downy shoots, which makes him think it is not B. pendula. They
don't have the plant any more, so he has no further information.
Iris,

+ + +
Are you sure you want to go there?
As I understand it the taxonomy of Betula is something else.
Just the difference between Betula pendula and Betula pubescens is enough to
fill up any amount of time (provided you can read Russian; if not, you can
add a few years to learn that)
PvR

"P van Rijckevorsel" wrote in message
...

Are you sure you want to go there?
As I understand it the taxonomy of Betula is something else.
Just the difference between Betula pendula and Betula pubescens is enough
to
fill up any amount of time (provided you can read Russian; if not, you can
add a few years to learn that)
PvR

Let's hear it for the Atkinson Discriminant Function! :-)

"P van Rijckevorsel" wrote
Are you sure you want to go there?
As I understand it the taxonomy of Betula is something else.
Just the difference between Betula pendula and Betula pubescens is enough
to fill up any amount of time (provided you can read Russian; if not, you
can add a few years to learn that)
PvR

Martin Rand schreef
Let's hear it for the Atkinson Discriminant Function! :-)

+ + +
I assume that is a way to learn Russian quickly?
PvR

In article , P van
Rijckevorsel writes
Martin Rand schreef
Let's hear it for the Atkinson Discriminant Function! :-)

+ + +
I assume that is a way to learn Russian quickly?
PvR

ADF=12 LTF + 2 DFT + 2 LTW - 23

(take the mean of 5 leaves from short-shoots)

LTF (Leaf Tooth Factor) - # of teeth projecting beyond line connecting
tips of main teeth at ends of 3rd and 4th lateral veins, subtracted from
the total number of teeth between these 2 main teeth.

LTW (Leaf Tip Width) - width in mm of leaf 1/4 distance from apex to
base.

DFT (Distance to First Tooth) - distance in mm from apex of petiole to
first tooth.

Positive values of ADF are B. pendula; negative values are B. pubescens.
Error rate 7%. Most errors are B. pubescens with slight positive values.

(Description taken from Stace.)
--
Stewart Robert Hinsley

ADF=12 LTF + 2 DFT + 2 LTW - 23

(take the mean of 5 leaves from short-shoots)

LTF (Leaf Tooth Factor) - # of teeth projecting beyond line connecting
tips of main teeth at ends of 3rd and 4th lateral veins, subtracted from
the total number of teeth between these 2 main teeth.

LTW (Leaf Tip Width) - width in mm of leaf 1/4 distance from apex to
base.

DFT (Distance to First Tooth) - distance in mm from apex of petiole to
first tooth.

Positive values of ADF are B. pendula; negative values are B. pubescens.
Error rate 7%. Most errors are B. pubescens with slight positive values.

(Description taken from Stace.)
--
Stewart Robert Hinsley

+ + +
Oh my, and here I was taking one quick look at the bark (from five to ten
meters distance)!
PvR

Positive values of ADF are B. pendula; negative values are B. pubescens.

You lost me. Can you please explain this in plain English?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

"Stewart Robert Hinsley" wrote in message
...
In article , P van
Rijckevorsel writes
Martin Rand schreef
Let's hear it for the Atkinson Discriminant Function! :-)

+ + +
I assume that is a way to learn Russian quickly?
PvR

ADF=12 LTF + 2 DFT + 2 LTW - 23

(take the mean of 5 leaves from short-shoots)

I think that should be
ADF=12 LTF + 2 DFT - 2 LTW - 23
otherwise a lot of B. pubescens is going to disappear from the world :-)

In article , Martin Rand
writes
ADF=12 LTF + 2 DFT + 2 LTW - 23

(take the mean of 5 leaves from short-shoots)

I think that should be
ADF=12 LTF + 2 DFT - 2 LTW - 23
otherwise a lot of B. pubescens is going to disappear from the world :-)

Yes, you're right. Apologies for the mistranscription.
--
Stewart Robert Hinsley

'Trost's Dwarf' has cut leaves, like a Japanese maple. Where does that leave
us?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

From: "P van Rijckevorsel"

"P van Rijckevorsel" wrote
Are you sure you want to go there?
As I understand it the taxonomy of Betula is something else.
Just the difference between Betula pendula and Betula pubescens is enough
to fill up any amount of time (provided you can read Russian; if not, you
can add a few years to learn that)
PvR

Martin Rand schreef
Let's hear it for the Atkinson Discriminant Function! :-)

+ + +
I assume that is a way to learn Russian quickly?
PvR




The best way I can think of is to search the web for "Russian Mail order
Brides" and peruse one of the many services that may come up. You will likely
find someone who can teach you Russian, quickly.

Sean



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