Anyone have any guesses?

[WhiskeyMike]

This popped up off our back patio.* Any ideas?* It has a spiney, hard stem.* The leaves sorta resemble maple leaves, but a little different.* They, too, are spiney.

[Newt]

Hi WhiskeyMike,

Knowing where this tree is growing would be most helpful.* A closeup of the leaves and trunk might also help.* I'm thinking it might be some type of hawthorne that may have hybridized, as they do this.

Newt

[WhiskeyMike]

Sorry, never thought of that.* It's growing in the midwest USA, near St. Louis.* Attached is a closer look at the stem.

[WhiskeyMike]

A closer look at the leaves

[Newt]

Mike, I have been looking at weed pics for hours.* At first I thought of giant hogweed and that lead me to others.* I'm not sure if what you are describing as thorns are actually thorns but might be considered bristles or hairs.* Generally, when something grows that fast and just appears in the garden, it's usually a weed.

I would suggest you ask at this botanical garden where several botanists answer questions.* The first link is their main site and the second link is where to post your question and pics.* Be sure to list your state and hardiness zone when you register as this site is in British Columbia, Canada.
http://www.ubcbotanicalgarden.org/fo...ffb27b3a8f929&
http://www.ubcbotanicalgarden.org/fo...splay.php?f=38

Please let us know what they say.* I can't wait until you find out.
Newt

[Newt]

Mike, I wonder if you ever got an answer from UBC Botanical Gardens.* I'm thinking this might be giant ragweed.
http://www.ppws.vt.edu/scott/weed_id/ambtr.htm
http://www.illinoiswildflowers.info/...nt_ragweed.htm

Newt