One story that I remember fondly from 2013 was the story of how an unloved invasive species found its way onto Canada's new polymer currency.

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Evan Dyer. (CBC)

Canadian money has long featured maple leaves on both bills and coins. But graphic designers apparently find the standard five-lobed Canadian sugar maple somewhat boring. And so the seven-lobed Norway maple leaf has been cropping up more and more on Canadian logos, including the symbol of the 2007 FIFA Under-20 soccer World Cup, held in seven Canadian cities, and the new logo of Wilfred Laurier University.

It's long been a pet peeve for New Brunswick botanist Sean Blaney, who says the European imposter is displacing the genuine Canadian article.

"It was only when I got one in my hand that I noticed that the image was clearly one of a Norway maple and not a Canadian maple," says Blaney. "It's quite different from any of our Canadian maples. We wouldn't think of putting a palm tree on Canadian currency, or a tiger or a baboon, and I think the same should go for Norway maple."

The tree botanists love to hate

The Norway maple was first introduced to North America as an ornamental by a Philadelphia merchant in the late 1700s. It soon began to spread in the mid-Atlantic and New England states.

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On the left is a photo of the Norway maple leaf, which botanists say appears on the new polymer bills. On the right is a leaf from the sugar maple, the Canadian species that appears on the national flag.

The tree is banned in Massachussets, where it is considered a threat to native species. In Canada, it is mostly an urban tree, having so far failed to displace native species in the wild. But it has already colonized Mount-Royal in Montreal, and botanists fear it may yet spread further.

The Norway maple tends to grow in thick, monoculture stands that kill off native ground cover and plants underneath them.

It does not boast the beautiful fall colours of native maples. Instead its leaves tend to turn a dull yellow and become covered with black "tar spots." One reason it has been extensively planted in cities is that it is considered resistant to pollution and road salt.

Bank of Canada denies Norwegian origin

But the Bank of Canada strenuously denied that the leaf resembled that of a Norway maple. Although it had an unusual seven lobes, the bank said it was actually a composite of several different native species. 

"The design for the frosted maple leaf window contains different aspects of various Canadian species of maple trees," said bank spokesperson Joanne Smith. "The intent was to create a design that appeals to Canadians' different perceptions of a maple leaf no matter which trees are more prominent in their area of the country."

There are 10 native maple species, but none of them normally has a seven-lobed leaf.

CBC News took the bills to the Canadian Museum of Nature to settle the matter.

University of Ottawa botany professor Julian Starr curates Canada's national botanical collection and specializes in plant identification. He has worked as a consultant to the Royal Canadian Mint, advising on plant accuracy in Canada's coinage. But the Bank of Canada, which makes banknotes, did not use his services.

"Without a doubt I would have said immediately that it would be best to make it look more like a native maple leaf. I mean this to me is just wrong," Starr said. "This could not be confused with a native species of Canada. I mean it basically looks like a Norway maple."

But the bank stuck to its guns. It had already printed 400 million $20 bills with that leaf. Later in the year the $5 and $10 bills came out with the same leaf.

The story provoked a minor kerfuffle and spread around the world, presumably because news programmers in other countries saw it as an amusing "kicker" or lighthearted news story: the Canadians who don't recognize their own national symbols.

To me the story said a lot about our disconnection from nature.

Graphic designers, who typically live in cities, are more likely to see this tree than they are to see one of our native species. And of the hundreds of people who must have seen this bill's design before it went to the presses, no one noticed the European invader that is displayed so prominently on the front.