Platycerium superbum, from Australia, is the most common of the "Giant Staghorns." These are solitary species characterized by huge shields, which form a nest. Platycerium superbum can also make impressive fertile fronds.
The plant in the picture above is growing on an oak tree, in Vero Beach, FL.. It never requires water, and tolerates draught and long rainy periods. This is the most cold-hardy staghorn, reported to take temperatures in the low 20s, if dry. In cultivation, over watering is harmful.
There is a form grown in Australia which has lobes around the shields. The photo below shows this trait, in a beautifully grown specimen. Keith Rogers, also in the photo, generously shared spores of this variety about 10 years ago. The trait may not be reliably passed to spore grown plants, although a few show signs of lobing. This is called Platycerium superbum 'Gympie Form'.
Platycerium superbum is incorrectly sold as Platycerium grande in the horticultural trade.