The Canning Club is a University of Oxford student society founded in 1861. It was established as a forum for discussing and promoting Conservative political ideology.
It is not to be confused with another Canning Club (formerly the Argentinian Club) which is a gentlemen's club in St. James' Square, London.
J.C.R. stands for 'Junior Common Room'. This is a college-based organisation which represents undergraduates in the University administration, as well as being responsible for co-ordinating practical matters and arranging social events. It is also the name given to an actual room which is available for the use of undergraduates.
Oxford colleges also have 'Middle Common Rooms' to which postgraduate students belong, and 'Senior Common Rooms' to which fellows (teaching staff) belong.
Other British Universities, including Cambridge, Durham and Reading, also use the 'Common Room' system.