The origin of the tree is Autralia, where it is know are oak or ironwood/beefwood. The name of the genus is Casuarina and there are more than 17 species in the family Casuarinaceae, almost all are native to Australasia.
In India they are known by different names in different parts, like Vilayati Saru in UP, Bihar, MP etc. ; chouk in Chennai and other southern part.
Well! no more gyan enjoy the beauty of the evergreen shrub and next time never forget to have a click in front of them!