Sonchus asper

Sow-Thistle (not a real thistle, but a dandelion.) Eurasian invader.

There are two different Sow-Thistles that are common in our area and they are practically indistinguishable; the only difference I can find is at the base of leaves. In Common Sow Thistle the base of the leaves comes to two points on each side of stem, while in Prickly Sow Thistle the leaf wraps around the stem. Downtown I see mostly Common, while on the the trails I see both, and on Camino Cielo I see Pickly. (I’m not sure I have enough data for making these generalizations).

Shiny tooled leaves with spines on the edge. Can grow up to 6 feet tall or so.