Orchid identification please.

I am hoping someone might be able to identify this orchid. This came as a gift from an elderly lady who tells me it is an Australian orchid from warm temperate east coast.

Presently the orchid is growing on an old piece of branch perched on top of a terracotta pot filled with free draining orchid mix. My thought was that roots developing over the old branch would enter the orchid mix and secure the plant to the terracotta pot.

I would greatly appreciate any assistance in identification of this plant. Thank you.

Orchid 1

Orchid 2

Orchid 3

Orchid 4

I would say its Bifrenaria Harrisoniae

Thank you Breeindy - Bifrenaria harrisoniae syn. Dendrobium harrisoniae

I just did a quick Google - comes up with a South American origin. Maybe the lady who gave the plant to me had her wires crossed regarding origin

Thanks again!

Great big plant! I'd repot it after the flowers finish and cut them old black bulbs and dead roots off. You may be able to put it back in the same pot or smaller, depending on how much you cut off. Looks a little dry but then it looks like it has alot of buds also. The clay pot would dry quicker than plastic.

http://davesgarden.com/guides/pf/showimage/10082/

I googled Australian Native Orchids ...that might be why I couldn't find it.
Not an orchid person so I did not recognize it.
Well done breeindy ^_^