Native to the southern foothills of the Alps, yellow corydalis (Pseudofumaria lutea) has been grown as an ornamental in the British Isles since late in the sixteenth century. It was first recorded in the wild plant in 1796 and became widespread early in the next century. In recent times it has expanded its distribution throughout the British Isles, although it remains little recorded in the Irish Republic [1]. As yellow corydalis has spread it seems to have adapted to new habitats; once it was restricted to crevices in walls and similar situations, now, in London, at least it seems able to colonise any bare ground. It is possible that climate change is stimulating greater seed production.
As an attractive plant which can rapidly spread, and was probably passed round between cottage gardeners, one would expect yellow corydalis to acquire a large number of local names. However, this does not seem to be so.
In their Dictionary of English Plant-names, 1886, James Britten and Robert Holland record lady’s pincushion, mother-of-thousands and pincushion as Devon names for yellow corydalis. A.S. Macmillan also records mother-of-thousands from Somerset [2], and collected fingers-and-thumbs from Stoke Abbott in west Dorset [3]. Yellow corydalis shares each of these names with nine or more other species (see the Local Names page on this website).
A more interesting name is Italian weed given to the plant in the Craven area of North Yorkshire, and recorded by Britten and Holland in a card index containing names accumulated for a supplement to their Dictionary, now housed in the Botany Library of the Natural History Museum, London. This name was given to yellow corydalis because it was ‘said to follow the Romans’.
Finally in issue 2 of her short-lived newsletter Plant Matters, autumn 1996, Ann Macfarlane records what must have been a very local name:
‘Yellow corydalis – Called Kitty Barnard in the Clywd [north Wales] village Glyndyfrdw after a Victorian lady who potted up the plant for sale in her garden. Another name for yellow corydalis is yellow fumitory.’
Thus it seems that the plant has acquired no more than seven local names in the British Isles.

1. C. Preston, et al., New Atlas of the British & Irish Flora, 2002: 119.
2. A.S. Macmillan, Popular Names of Flowers, Fruits, etc., 1922: 197.
3. ibid.: 105.

Addenda
PLA contains an additional name for yellow corydalis: poppers, used for both it and balsam (Impatiens spp.) in Wiltshire, and presumably referring to its explosive seed-capsules [Rowde, Wiltshire, February 1982].

Two additional names, recorded Criggion, Montgomeryshire, are given in The North Western Naturalist 14: 216 (1939): canary, and canary creeper.

Image:  Wadebridge, Cornwall, April 2014.

Updated 21 December 2020.