Paula and I were in the backyard of our new house and noticed a tree that had a citrus-smelling fruit. Since we couldn't figure out what the "mystery fruit-like substance" is we figured that the donrockwell.com community could help. Below are some pictures.

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This is a picture of the fruit in the tree.


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The "mystery fruit" has a citrus smell and looks similar to a lime.

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However, when smashed open, well, I don't really know what it looks like.

So, does anybody have a guess? Have we stumbled onto a culinary goldmine or a nuisance that will continue to get stuck in our lawnmower?

Thanks!

if it looks and smell like a lemon or lemony, it's probably yuzu. I have one at my fence line. Are they around 2 inches in diameter?

The winters around here are too cold for true citrus trees. My guess is that it is an Osage orange.

http://www.cnr.vt.edu/DENDRO/DENDROLOGY/sy...sheet.cfm?ID=57

Yes, they are around 2 inches in diameter. However, they are green and most resemble a lime as opposed to a lemon. I don't know if they eventually change color since we just moved into the house. Are yuzu green before they turn yellow?

The stay 90% green until they fall off the THORNY(very) tree. I've never seen one turn yellow at all. You do have nice 2 inch thorns on that tree, don't you?

Nope, no thorns on the tree. The tree is massive...at least 50 feet tall.

What color is the blossom?
If it is white, I would assume that it is a trifoliate orange.

Hmmm, that changes my answer then...that tall and no thorns...more research is needed here. Are you anywhere near Alexandria City Hall on Saturday mornings around 6:00am? There is a VT horticulturist there on market Saturdays. If you bring a sample and a leaf, he may be able to identify it for you.

If only we had clear photos, especially of the leaf arrangement, or a cross-section of the fruit. Smashing doesn't count

From the foliage visible in the top photo, my guess is it's a black walnut, with immature fruit. Leave some on the tree and see what they look like in October. If so, then what you have is both edible (although not necessarily a goldmine) AND a lawnmower nuisance. Or it could make a nice coffeetable someday...



More photos.

About.com entry for Black Walnut.

I'm going with Ol Ironstomach here. My grandfather had several black walnut trees on his farm, and in the fall after they fell from the tree, would drive his tractor back and forth over them to break open the husks and get at the nut itself. Note that the husks can leave a dark stain, so take care.

I think this is the winner. Based on your photos and some additional reading, I am fairly certain that it is a black walnut. Looks like a ton of work to harvest, so we shall see how adventurous I become.

Thanks to everybody for their help and input. I knew that this community would come through! If we find any other culinary puzzles in our backyard, you all will be the first to know.