Poison Hemlock, Conium maculatum
I have been battling this extremely poisonous plant for nearly 29 years! It grows in damp ground, like down at the creek that flows about 100 yards away. The cats used to bring its seeds up to the house, along with Queen Anne's Lace, Bedstraw,Galium, and other 'sticky' seeds. I don't know how many pairs of socks we had to throw away after Selene went 'hiking' through the field and orchard that used to sit between us and the creek.
Anyway, this is the plant that killed Socrates. A prefered method of death penelty of the ancient Greeks. It will bloom into lovely umbrels (umbrella shaped) of small flowers, like a loose version of Queen Anne's Lace, Daucus carota. The stems are streaked, spotted and sometimes all over colored with purple. The stems are hollow. AND THE ENTIRE PLANT IS POISONOUS!
I donned my gloves and pulled up a patch about 2 ft square. I have kept after this plant yearly. We have not had a cat in over 10 years who brought up the seeds from the creek. So these seeds are at least 10 years old. Yes, some seeds are viable for a VERY long time.
I taught Selene about poison hemlock when she was just four years old. In terms of, 'If you put any part of this plant in your mouth you will die. There is nothing that will save you.' We kept at the warnings clear through grade school. If she found a plant in the garden, she would come get her Dad or me to pull it.
Even if the smallest part of of the plant is ingested, get the person to medical help immeadiatly! There is no home cure.
This is not meant as medical advice or plant identification. If you find a plant you cannot identify, see your local Extension Office. If someone ingests an unknown plant call your Poison Contol Hotline with as much of the plant avaiable as possible to identify it.