MADISON, Wis. — Wisconsin wildlife officials are warning people to be on the lookout for a couple of poison plants.

Department of Natural Resources plant ecologists say poison hemlock and wild parsnip are becoming more common along roadsides. The sap from poison hemlock contains neurotoxins that can be absorbed through the skin; the story goes that Greek philosopher Socrates died after drinking poison hemlock.

Wild parsnip sap, meanwhile, can cause severe skin rashes, blisters and discoloration.

DNR ecologists say poison hemlock has smooth stems with blotches or purple spots, tiny five-petal white flowers and triangular, lacy leaves. Wild parsnip has small yellow flowers and diamond-shaped leaflets similar to celery.

They say the best way to control the plants is mowing them during their flowering stage.