Why The Daisies Are Not All White

Uncle Rob says:
Once the daisies all were white,
Till a baby fellow
Ate his supper down one night,
And stained his face all yellow.
Smeared with butter, off to bed
Crept the sleepy flower.
"Fie!" the good nurse dew-drop said,
Come now to my bower.
"Let me wash you clean, I pray,
Like the pink and rosy."
But the daisy pulled away
Like a stubborn posy.
All unwashed he went to sleep,
Naughty little fellow.
Ever since he's had to keep
That great patch of yellow.
So Uncle Rob says.