A South American Allium
Here is a plant with a nightcap; or, if you prefer, a dunce-cap. The protective covering of the flower-bud has burst open, but has not been discarded; hence the curious effect. This is not, as might be supposed, a mere accidental individual peculiarity, but is characteristic of the species. It might be difficult to guess, however, what protective function the nightcap subserves.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 7 Chapter 5