Google+ android app now supports landscape mode, just tilt your smartphone and you’ll find the google+ app automatically switching to landscape mode.
To see for yourself, just install the app from google play or update from your phone to the latest version 18.104.22.168545355.
Here is the screenshot of What’s hot stream looks like in landscape mode
Here is another screenshot of Posts stream in landscape mode
This allows flipping through the stream the same way you would do it on a tablet. Looks great, try it out.