CENTAUREA macrocephala is quite a mouthful....even for a botanical name. It does, however, have a number of less intimidating common names including 'Knapweed', 'Yellow Hardhat' or the one I am most familiar with 'Armenian Basket Flower'

This is a hardy summer-flowering perennial w/ bright lemon yellow, thistle-like flowers encased in chestnut- brown bracts......bracts which open to expose that crown of rich yellow florets. Single flowers grow atop 3'+ very thick and sturdy stems. The light brown bract in the image here actually looks exactly like a woven basket prior to the yellow blossom appearing- hence the 'Basket' part of the common name.

I have two plants in their 8th year at my place....each has over a dozen large (3-4") flowers . The foliage is not particularly attractive but the basket-like bract is fascinating to watch as it opens- especially as the yellow blossoms spring forth. Taken on a cloudy afternoon I was concentrating on showing the many yellow florets when I took this photo.....didn't even notice the little green 'visitor' until the image was on my computer.