Oyster Plant
(Tragopogon dubius)

The genus name Tragopogon comes from two Greek words meaning "goat beard". A related plant is Tragopogon porrifolius. It is very similar, except that it has a purple flower head.
The salsify plants were introduced from Europe by early settlers, as a food source. Their roots have a flavor somewhat like oysters. They have rapidly spread over the continent, and are now common weeds along roadsides and ditch banks.
The fruiting heads are like those of a dandelion, but much larger -- about 4 inches in diameter. They are very showy and conspicuous.