from The Century Dictionary and Cyclopedia
- n. A genus of composite plants of the tribe Senecionideæ and subtribe Tussilagineæ, characterized by scapes bearing many partly diœcious heads of flowers with involucral bracts in but one row.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. genus of rhizomatous herbs of north temperate regions: butterbur; sweet coltsfoot
Sorry, no etymologies found.
Because of this it may be a good idea to avoid using herbs such as conifrey, borage, senecio, coltsfoot, boneset, and petasites during pregnancy and for infants and young children.
Another species, the Butter bur (_Tussilago petasites_),  is named from _petasus_, an umbrella, or a broad covering for the head.
Look, here is a very lovely parallelogram of green surrounded by petasites.
Leafy architectural statements like silvery cardoons, echiums, ornamental rhubarb and petasites fill the beds and borders with their pointed, jagged and dinner-plate-sized foliage.