If EXPR is omitted, splits the $_ string. If PATTERN is also omitted, splits on whitespace (after skipping any leading whitespace)

As a special case, specifying a PATTERN of space (' ' ) will split on white space just as split with no arguments does

Those little factoids escaped me. I suppose it's time to start reading 'Programming Perl' for the third (or is it fourth?) time. No matter how many times I read it I always pick up something new