I was yanking up various weed plants, all of which I mentally file under 'dandelions', and decided there must be two or three varieties present based on the varying ease of removal. They all have a very similar type of flower, but the leaves and stems are quite different in terms of color, shape and size. My biology knowledge is strongest in terms of humans, in spite of my one quarter of Native Plants of the Pacific Northwest, so I'm in the position of being mildly curious with just enough information to go wrong. I do know that plant morphology is quite variable within species, and that plants are notoriously promiscuous in reproductive strategy, so I wouldn't be surprised to find them all to be dandelions, but nor would I be shocked to find them utterly different species.
So far the wasps/hornets/non-honeybee flying stinging things that were troubling me last fall have not made an appearance. Maybe the really cold weather we had this winter was useful after all.