Korydalis = lark's head. Also known as yellow fumitory...
And down...the furrow dry
Sunspurge & oxeye
And laced-leaved lovely
The Woodlark, Gerard Manley Hopkins, 1844-1889
It grew in the old brick wall of my garden in Alexandria, years ago, and self-seeded easily - maybe too easily for some. It is like a little yellow bleeding heart, but keeps flowering, not giving up after spring. Some sun, some shade, and a little, very little place for its roots.
I went to the BBG to do some native plant research - which pictures I shall inflict on the blog this weekend - for the park-to-be...