G+ allowed Hangouts only via Desktop from its release. As, G+ mobile app on Android is updated to 3.1.1 and now it has an ability to participate in Hangouts on Air from your mobile device. Google is allowing teens also to create and join hangouts from their mobile.
There are also other features in this update is, Shortcuts for posting to your page, Can report abuse on Events pages and a Floating timestamp in photos view. The update is from August 15th. Now, you can download and install the updated G+ from Play store.
Is it a Good Change ?? Reply in comments.