Haemanthus
A red flower that grows on Mars, on which the people of Lykos have made a tradition. It's an emblem of Eo.
The name means blood blossom. It grows in Martian soil, even down in the mines. As a child, Eo tucked one into the boot of Darrow's father when he was hanged.
Afterwards the flower is what Darrow carries of her through all that he becomes.