ID: Thorny Tree at ASU
I was wondering if anyone could help me with an identification. I bumped into a very thorny tree with simple, glossy, variably-shaped leaves on the ASU Tempe Campus. More specifically, the tree is on the east end of Discovery Hall, just off the Cady Mall walking area. The leaves are alternate and mostly round, although some of the shoots bear leaves with some blunt lobing; some have notched apices. The bark is smooth and gray but the plant is still pretty young (10-15' tall). The leaves are very glossy. No signs of fruits or flowers. The thorns are about 3-4" long on average and are simple. I just graduated from ASU (plant biology) and this is the only plant on campus I haven't been able to ID yet. Any ideas?