Therefore, to arms! And, father, do but think
How sweet a thing it is to wear a crown,
I cannot rest
Until the white rose that I wear by dyed
Even in the lukewarm blood of Henry's heart. (1.2.28-29, 32-24)
When Richard is trying to convince York to fight Henry, he uses this description of war. It's poetic, it's symbolic, and it's downright gross. But hey, it does get across the fact that Richard is out for blood if someone stands between his dad and the crown. He's always willing to fight for his crown—er, his family's crown—er, actually, with Richard, it's never totally clear. For more on the white rose, head on over to "Symbolism, Imagery, Allegory."