Looks like a ponytail palm, but they're tropical and not hardy here. Perhaps the zoo has it in a giant buried pot and brings it inside for the winter.

I would say Ponytail Palm too. Botanical name is Beaucarnea recurvata. Don't know how old it is, but the one in the picture is definitely an older plant which is probably taken inside every year. I think I have seen these at Wal-mart & Lowe's the bulbs on smaller plants are usually about an inch across wheres as some of the bigger ones I have seen are 3-5 inches across. I recently saw one of these in the palm house at the San Antonio Botanical garden that would make this one look like a seedling. It was HUGE!! Really neat to see. Hope you find one, it is a very easy plant to grow.

Thank you! Okay, I will grow one in a big pot. I love that tree. :)

Jo

I've been meaning to look up the Oklahoma Proven Tree list for you.

Here's an article:
http://www.ardmoreite.com/community/x656692905/The-best-trees-for-Oklahoma

http://oklahomaproven.okstate.edu/

Hope that helps.

If you want to see a giant pony tail palm growing in a container indoors, go to the BOK Tower downtown. It is either on the 720 (2nd street) level or up the escalators to the plaza level where the bank tellers are. I can take a picture at work and post it if you like.