When is a cork bark elm, a cork bark elm?

[leatherback]

I know.. Sounds like a silly question BUT.. I am finding a lot of contrasting names for cork bark elm, and I am not sure whether there is actually just 1 cork bark elm..

In trade, one often finds cork bark elms labelled as "Zelkova Nire" (Which does not exist and is mislabelled). But also Ulmus parvifolia 'cork bark', which I believe to be the same species.
from a website, zelkova nire:



Then I have one tree labelled as cork bark elm / Ulmus parvifolia 'corticosa'


Next to this, I have come across regular Ulmus minor with very heavy corking on older specimens that seem to take many years to cork up on branches.
I think this is one of those:


Finally, I have a plant purchased as Ulmus suberosa, which probably is a mislabelled Ulmus minor 'suberosa'.
This has cork on 1 year old branches already


Are all of these the same, and mis-labelled, or are there many different species / cultivars that produce such heavy corking that they are worthy of a common name "cork bark elm"?

 

[Shibui]

There are definitely quite a few cork bark elms.
Ulmus parvifolia 'cork bark' is the usual one we refer to as cork bark elm but it has been known under a range of names down here too - Ulmus davidii; Ulmus parvifolia var Davidii;
Ulmus parvifolia 'Seiju' also develops corky bark but much smaller leaves.
Ulmus parvifolia 'Nire Keyaki' aka Hokkaido elm also develops thick, corky bark.

Ulmus parvifolia grown from seed can have a wide range of bark type from smooth, peeling through light corky bark to thick, heavy corked bark so I'd expect there to be more selections based on bark types and some individuals grown from seed may also have ben mistakenly labelled as any of the previously named cultivars, further complicating the problem.

Many of the other elm species also develop thick, corky bark. Others have corky 'wings' on the smaller branches so I would not be surprised to see some selected cultivars of some other species based on bark.

I've never put a lot of store in the names. I'd rather look for the merit in each individual bonsai.

 

[Betula1]

If seed grown they are likely to contain a genetic mix since they are wind pollinated, so bound to be variable .

 

[Bonsai Nut]

There are definitely quite a few cork bark elms.
Ulmus parvifolia 'cork bark' is the usual one we refer to as cork bark elm but it has been known under a range of names down here too - Ulmus davidii; Ulmus parvifolia var Davidii;
Ulmus parvifolia 'Seiju' also develops corky bark but much smaller leaves.
Ulmus parvifolia 'Nire Keyaki' aka Hokkaido elm also develops thick, corky bark.

Here in the states, we generally see them listed as Ulmus parvifolia 'cork bark' or 'corticosa'.
Ulmus parvifolia 'Hokkaido' is considered a separate cultivar, and is an extreme dwarf, and though it has very corky bark is more known for the tiny leaves - and its general weakness, brittleness, and slow growth.
Ulmus parvifolia 'Seiju' is also a separate cultivar, somewhere halfway in-between 'corticosa' (which has normal leaves) and Hokkaido. It was actually created from a sport on a Hokkaido tree - a random genetic variation with stronger growth and larger leaves. I personally consider Seiju the best dwarf corky cultivar.

Believe it or not, Ulmus minor is not very common here - at least in comparison to Chinese elm and the native US elms species.