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

Seeds last up to about 20 years in the soil, and can travel miles on the
wind because they have a little "parachute" of hairs (pappus), and also
many songbirds eat the seeds.

I didn't see songbirds eating; but I did watch this one bee with interest.
http://www3.picturepush.com/photo/a/...g/13420046.jpg

I'm not sure what it was looking for - but it kept digging away on
the purple stuff (which is just about the only non-thorny thing):
http://www4.picturepush.com/photo/a/...g/13420047.jpg