Who wrote this poem?

[Hardy Parkerson]

Anybody know the name of the poet who wrote this poem which is said to have been J.F.K.'s favorite (with apologies to the poet concerning form)?

Young man, I have seen
thee strolling
In the stillness of the park.
Day by day, hand in pocket
Of your slim, familiar jack,
Twilight into dark.

I have come come to
know your whistle,
Know your collie,
know your cap.
Have seen the straggling
sunlight hold you,
Watched the emerald
grass enfold you
In its loving lap.

With your lichened
switch I see you
Flick the mushrooms
in your way.
And I know what
you are thinking.

Would that through
the soft mist falling
You could hear
a stranger calliing:
Stay!