It is a member of the lettuce family. Normally would have a tap root but because it does not probably plant was cut off with a bit of crown root tissue and regrew.

This is one of the ones that I like to watch. Next year it would put up a tall 4-8 foot stalk with either yellow or blue flowers. The finches like the seeds so seldom do I have more than one or two plants.

Thanks, maifleur. The closest I could get from my references was yellow starthistle (Centaurea solstitialis), but the foliage just doesn't seem to be a perfect match. When I get a chance I will go through a few in the genus Lactuca.
hortster

Pretty sure its sow thistle or Sonchus oleraceus,also edible.

Hey, wombat196 - after googling Sonchus I must admit that the distinctly triangular leaf tips and basal leaf whorls are very similar. If so this plant is indigenous to both the USA and Austrailia? Now I wish I hadn't pulled it just so I could get a positive ID.
The confusing thing is the rootstock. The link below shows a tap root with smaller, more fibrous extensions. When I pulled it there was no tap root at all with the fibrous roots beginning immediately at the crown. And as it had been within a tomato cage, "hiding" and safe from the hoe, I am sure that it had not been disturbed before (which might have caused the loss of the tap root). Darned thing is an anomaly.
Thanks for the imput!
hortster

Here is a link that might be useful: Sonchus oleraceus rootstock

My guess is latuca candensis. Sonchus oleraceus is sissel, it graps the stem then sends two points beyond it. More so, the Sonchus start out with oblong leaves and don't develop lobs until later in their growth cycle. The l. candensis looks the same as an adult as it does at this stage, only larger. Should have yellow blossoms. Edible. Visit www.eattheweeds.com

Hey, zorba - since maifleur's comments earlier I have been through all the latucas I can find and can't get a convincing match. The plant looked more like the plant in your post in Name That Plant forum, "OK, it is probably a mustard, but which one?" The lobing along the length of the foliage was similar, but yet different from mine and the tips on mine were more distinctly triangular.
Should this critter occur again in my garden I will let it grow and post more pix.
Thanks, hortster

Well, my plant in "name that plant' forum is probably a first year lepidium virginicum.I ws just looking for confirmation. Your plant is not that. It really looks like a young L. canadensis to me, which has high varibility. If it is a mustard, a taste of the leaf will tell you within a few seconds. It will be peppery.

LOL. Zorba, I have learned from personal experience not to taste-test any plant that I can't ID. Learned the hard way (won't go into that). However, I will keep my eye out for that critter for more pictures and your further opinion!
hortster