Cow Parsnip, Cow-parsnip, Common Cow-parsnip, American Cow-parsnip: Heracleum maximum (Synonyms: Heracleum douglasii, Heracleum lanatum, Heracleum sphondylium ssp. montanum, Heracleum sphondylium var. lanatum, Pastinaca lanatum) - A robust plant with one to several erect, thick, hollow stems up to 2 meters high. The leaves are basal with one to several slightly reduced stem leaves. The broad leaves are ternately compound with palmately veined, mapleleaf-like leaflets.