This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Introduced. Biennial. Propagates by seeds.
Time of bloom: June to August.
Seed-time: August to October.
Range: All parts of the United States and Canada.
Habitat: Roadsides and waste places.
"Pastus" means food, and, as its name indicates, this is the garden Parsnip, long ago "gone to the bad," for its thick, white, fleshy root is no longer a food but a poison, even after it has been cooked - a fact which is every year demonstrated by several deaths.
Crown leaves of the first year large, often eighteen inches in length, with long, flattened, and grooved petioles: pinnate, the segments thin, sessile, ovate, coarsely and sharply toothed, often cut-lobed. Fruiting stem two to four feet tall, hollow, grooved, smooth, its leaves much smaller and clasping. Umbel compound, without involucre or involucels, the flowers very many, small, and yellow. Carpels nearly one fourth of an inch long, broadly oval, much flattened, surrounded by a thin, corky ridge which helps them to float on water or to be carried by the wind. This weed, like the Wild Carrot, serves as host to the fungus which is so injurious to celery, and will infect that plant when it grows near it.
Hand-pulling when the ground is soft in spring. Spudding or hoe-rcutting the root leaves from their crowns, an operation best performed in late autumn or early spring. Plants that survive to send up flowering stalks should be cut while in bloom.