The Collaborative International Dictionary
Senecio hieracifolius
Hawkweed \Hawk"weed`\ (-w[=e]d`), n. (Bot.)
A plant of the genus Hieracium; -- so called from the ancient belief that birds of prey used its juice to strengthen their vision.
A plant of the genus Senecio ( Senecio hieracifolius).
--Loudon.