unknown shrub with spines in Pennsylvania

janet_e(6B PA)July 12, 2014

This shrub completely stumped two professors of ecology and several officers in the Philadelphia Botanical Club, but I bet someone here will be able to identify it.

Besides the photo below, I have posted larger photos.

The shrub was growing wild on an island in a river that runs through Philadelphia. It's not something I've ever seen in the wild before; it may be a garden escape.

The shrub was around 6' tall. As you can see in the photo, it has sharp spines, but is otherwise rather nondescript. It didn't have any flowers or seeds to help with identification.

Any ideas?


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I believe it's the descendant of a Bradford Pear, the wild Callery Pear.

It's exceptionally invasive...esp in wetlands (from what I see around Tulsa).

Yet another alien plant introduction gone wrong.....I'm quite surprised your "experts" were unable to identify it.

    Bookmark   July 12, 2014 at 8:48PM
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missingtheobvious(Blue Ridge 7a)

Agree with dbarron. The descendants around here tend to be spiny.

    Bookmark   July 12, 2014 at 9:22PM
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janet_e(6B PA)

I really don't think this is Pyrus calleryana.
We see a lot of escaped callery pear around here, and in my experience the escaped trees always look pretty much like the variety 'Bradford.' This shrub looks quite different. You can't tell from the photo, but the shrub's leaves are somewhat hairy, whereas Pyrus calleryana leaves are hairless. Pyrus calleryana leaves are also glossy, somewhat leathery, and toothed. The mystery shrub leaves, in contrast, aren't glossy or leathery, and they are completely untoothed.

I would believe that an escaped Pyrus calleryana could revert to being thorny, but I've very doubtful it would change all those leaf characteristics.

    Bookmark   July 12, 2014 at 9:30PM
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Carrie B

Do you have any photos of the entire plant?

    Bookmark   July 12, 2014 at 9:40PM
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janet_e(6B PA)

Unfortunately, I don't have photos of the whole plant. It had arching branches, so it looked like it's really a shrub and not a tree. The bark was greenish on the twigs, nondescript on the mature wood.

    Bookmark   July 12, 2014 at 9:52PM
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lycopus(z5 NY)

Looks like Maclura pomifera to me

    Bookmark   July 12, 2014 at 10:55PM
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saltcedar(Sunset zn 30/usda 8b)

Looks like Maclura pomifera to me too.

    Bookmark   July 12, 2014 at 11:29PM
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I found this link, which seems reliable, Maclura seems to fit

And the leaves don't really look like Pyrus

Here is a link that might be useful: Description Maclura

    Bookmark   July 13, 2014 at 3:51AM
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I typed maclura last night, and then deleted it. The leaves are identically shaped to a maclura but the size in reference to the coin has me puzzled. They seem smaller than they should be. Don't be influenced by maclura not being indigenous to Pennsylvania. They were planted as hedgerows in farms and a very common sight even in my youth...but not so commonly seen anymore as the old ones die off. I started a run of maclura two years ago from seed just for old time's sake and they'll be planted at the lot line for wildlife. Mockingbirds love to nest in thorned trees.

    Bookmark   July 13, 2014 at 7:20AM
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janet_e(6B PA)

Maclura pomifera is right! You guys are awesome!

Calliope, some of the leaves are the typical size for Maclura. The ones in the photo with the quarter happened to be some of the smaller leaves.

    Bookmark   July 13, 2014 at 8:24AM
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Thanks............as many details as possible help with the IDs.

    Bookmark   July 13, 2014 at 9:49AM
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