Can anyone explain to me why the scalar $ENV doesn't show up in a package with its "fully-qualified" package name?

    % cat xxx.pl
    package script;

    $env = 1;
    $ENV = 2;

    print "\$env = '$env'\n";
    print "\$ENV = '$ENV'\n";
    print "\$script::env = '$script::env'\n";
    print "\$script::ENV = '$script::ENV'\n";
    % perl xxx.pl
    $env = '1'
    $ENV = '2'
    $script::env = '1'
    $script::ENV = ''
    %
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I suppose this has something to do with the special status of %ENV, but that sure seems to run counter to the usual distinction between a same-named scalar and hash.

This behavior is consistent on Perl 5.00345 and 5.6.0, so it's not a version-specific bug, at least...