On Wed, 26 Jun 2013 15:42:03 +0000, Kay Lancaster wrote:

Try pulling one up... you may find they're attached to an underground
root and stolon system, in which case you may be dealing with
Canada thistle, Cirsium arvense, a noxious weed* in California

Hi Kay,

I started pulling one up, then another, and another, and another,
until ... after a long while ... I filled my chest-high green recycling
bin with the thistle!
http://www1.picturepush.com/photo/a/...g/13419889.jpg

I'm not sure how they process those things at the town recycling
center - but those thistle thorns are nasty!
http://www1.picturepush.com/photo/a/...g/13419894.jpg