This is the time of the year that thistle is everywhere.  I walk my dog by some thistle every morning, and decided to photograph a bloom progessing

Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles often occur all over the plant – on surfaces such as those of the stem and flat parts of leaves. These are an adaptation that protects the plant against herbivorous animals, discouraging them from feeding on the plant. Typically, an involucre with a clasping shape of a cup or urn subtends each of a thistle's flowerheads.

Thistle is the floral emblem of Scotland

You can find more info here:  http://en.wikipedia.org/wiki/Thistle