What is this plant?

A tree with oppsite simple leaves, stem with thorn
Anybody has ideas?

 

See if this fits Symphoricarpos albus Snow berry.

 

No thorns on Symphoricarpos albus.

 

Please can you tell us where your pic was taken?
Washington D.C?
Botanic garden?
Further clues may help.

 

Probably, some kind of Canthium from Rubiaceae.
The leaves are opposite and the branches with paired thorns, the flower structure is also similar:
http://chiujai113.blogspot.com/2010/07/canthium-horridum.html
Many species - some of them may be cultivated in garden:
http://en.wikipedia.org/wiki/Canthium

 

Thanks a lot! It should be Canthium horridum.
I took pictue just from South China.
Great help from all of upstairs. Thanks.

 

Ahh! That makes sense.
It would greatly assist us all if you want future plants id'd, if you tell us where the pic is taken.
Sometimes the time of year the pic is taken is also relevant.
Thanks.