From my A-level knowledge, I'll go with coronary arteries.
Coronary vessels carry blood to and from the muscles in the heart, and arteries carry blood to the capillaries... But that's just an (intelligent) guess on my part. I'm not sure.
A single flow'r he sent me, since we met./All tenderly his messenger he chose;
Deep-hearted, pure, with scented dew still wet - One perfect rose.
I knew the language of the floweret;/'My fragile leaves,' it said, 'his heart enclose.'
Love long has taken for his amulet/One perfect rose.
Why is it no one ever sent me yet/One perfect limousine, do you suppose?
Ah no, it's always just my luck to get/One perfect rose.