It's a Platycerium bifurcata, looks great. They're not native to Mexico so it would have been a garden plant there. Mounting boards are needed when they're small to get them started. As they get larger they can "swallow up" the mount but still be okay provided the support they're suspended by is still good. Tie it up with something durable, the nest fronds will cover it up fairly quickly.

Thx, mounted it on a new board today and am going to get some moss to put behind it. It may not have come from Mexico then, I assumed it did due to all the orchids, elephant ears, bromiliads, and other ferns she brought back from Central Mexico.

Platycerium bifurcata is from Australia. A lot of Platycerium species are from Australia, New Guinea and South East Asia. Also some from Africa/Madagascar but only one from South America (Bolivia/Peru). They're an interesting group of plants, some quite spectacular. Your grandmother might have picked yours up from a garden or nursery while in Mexico collecting plants.

It's awesome nevertheless!

Beatiful! in Fl they hang them under huge trees they seem to love it they are huge

Thought I would share what it looks like a year later. I need to find one of those net hangers some grow them in.

It's looking very nice. Once they're larger a backing board becomes a bit impractical. Trees are far better, but a "net hanger" sounds good.