As we said last August,London Grammar combines the atmospherics of The xx with the vocal Flo-urishes of Florence (and her Machine).  The band went on to appear on many Best of 2013 lists for their album If You Wait and its sublime songs.  Last night London Grammar made their American television debut on Late Night With Jimmy Fallon.  They performed the stentorian Strong and Wasting My Young Years (the latter a web-exclusive).  Fallon wasn’t the only one to be impressed (though we’re curious if the band can captivate for an entire set).  Check ’em out below.