"Arkansas Love Poem" joke

Susie Lee done fell in love,
She planned to marry Joe.
She was so happy 'bout it all,
She told her Pappy so.
Pappy told her, "Susie Gal,
You'll have to find another.
I'd just as soon yo' maw don't know,
But Joe is yo' half-brother."
So Susie put aside her Joe,
And planned to marry Will.
But, after telling Pappy this,
He said, "There's trouble still.
You cain't marry Will, my gal,
And please don't tell yo' mother,
But Will and Joe and several mo'
I know is yo' half-brother."
But Mama knew and said "My Child,
Just do what makes yo' happy.
Marry Will or marry Joe,
... you ain't no kin to Pappy."