Google Android Tablets are getting it today. Apple iPad owners would get it in the near future.
Google has optimized the Google+ mobile app to suit the Tablet interface. It is not like the desktop version at all.
Google spoke about the Tablet optimized app:
A beautiful stream that styles content based on popularity, type and orientation
A “lean back” Hangouts experience that’s great for the couch or common room
Crisper text, fuller photos and easily-tappable actions like +1 and comment
