Why did the duck lose his doctor license? Because he is a...

I stand up tall upon the green, One little blade, so fresh and clean.

I wear a crown of velvet, though I never ruled a land, I flutter through the summer air, a wanderer bright and grand. My children crawl on milkweed leaves before they take to flight, A king of the meadow in a coat of orange and white.

I chase away the darkest night to wake up the sun, Or I drape the heavy shadows when someone's life is done. What am I ?

No engine, no sail, just you and two sticks. I glide when you pull with gentle flicks. On lakes I wander, calm and slow, What am I that rows where breezes blow?