@eddy: This description is from a previous post of this plant:
Salsify, sometimes known as oyster plant, produces edible roots said to taste like oyster... I haven't tried it (yet). This is also an introduced plant and is found near my home possibly because it's predecessors were planted for food. I live near an old homestead that was built in 1907. From the relics I've found on my property, I wouldn't be surprised if there wasn't a cabin here long ago. The seed heads are sometimes five to seven inches in diameter.