Yellow Corydalis Pseudofumaria (corydalis) lutea

I am an amateur naturalist trying to discover everything living in my garden.

Growing wild under the hedge at rear of my garden (at (0.8,2.0) - see here) are a number of patches of the yellow-flowered plant seen in photo 1 (taken back in early summer) . Photo 2 (click on photo's to enlarge) shows a close up of the pretty, trumpet-shaped flowers.

A short time spent with my copy of the excellent Wildflower Key (Francis Rose, Warne 2006) and I'm confident in identifying my plant as Yellow Corydalis (Psudeofumaria (Corydalis) lutea).

From the book above I learn that the plant family the Fumariaceae (the Fumitories) are related to the poppies (see here). The book lists eleven British species. From Wikipedia's entry however, it seems there is some debate amongst botanists as to whether the the Fumariaceae truely constitute a plant family.

The book describes Yellow Corydalis as introduced to Britain from E.Europe, though "possibly native in Kent". I can say that having learnt to recognise it, I've found it to be quite common, growing wild in Oxfordshire.

Confusingly, the official Latin name for Yellow Corydalis has changed from Corydalis to Pseudofumaria, to reflect that fact that the members of the former plant genus have simple stems whilst the latter have branched stems.

Turning to the internet I can find almost no information specific to my Yellow Fumitory (if anyone can point me to some do please leave a comment). I have come across a range of descriptions of its cousin pink-flowered cousin, Common Fumitory (Fumaria officinalis) however. Common Fumitory is distinguished by having a single seeded fruit (achene) whilst the other fumitories (including Yellow Corydalis) all produce capsules containing multiple seeds.

My copy of The Englishman's Flora (Geoffrey Grigson, Paladin) has no entry on Yellow Corydalis, but once again does discuss Common Fumitory. It seems there is some debate as to whether the name 'fumitory' refers to the pungent, eye-watering smoke that the plant supposedly emits when burnt, whether it is a reference to the 'smokey' colour of the foliage or whether it is a reference to the 'nitric-acid-fumes' smell of the roots. Referring to the second possibility, Grigson quotes William Coles' description of the foliage in his book Adam in Eden (1657) as

"a whitish blew colour as smoak is"

He also gives a rather nice quote from a Stockholm medical manuscript (c.1400)

"Fumiter is erbe, I say,
That springyth in April and in May
In feld, in town, in yerd and gate
There land is fat and good in state"

The poetry prize has to go to Jon Clare who (as I discovered from this site) writes:

"And Fumitory too, a name
Which superstition holds to fame,
Whose red and purple mottled flowers
Are dropped by maids in weeding hours,
To boil in water, milk, and whey,
For washes on a holiday,
To make their beauty fair and sleek,
And scare the tan from summer’s cheek"
(John Clare, quoted by Ann Pratt, ‘Wild Flowers’ (1857)

Can any maids out there report having tried this?!