This popular garden flower often escapes, and where a patch has once been planted, it reseeds itself year after year, spreading to wherever the seeds are carried by rain and gravity. It’s known by a large number of common names, among them Persian Jewels and Rattlebox. The latter name refers to the seed pods, which grow to balls about an inch in diameter that rattle when the seeds ripen and dry. These plants were growing on a bank in Beechview.
For Gray’s description of the species, see the Nigella damascena reference page.