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Pseudofumaria lutea (L.) Borkh., Yellow Corydalis

Account Summary

Introduced, neophyte, a rare garden escape. European temperate, native range restricted to foothills of SW and C European Alps.

1946; MCM & D; Newtownbutler.

May to September.

Growth form and preferred habitat

A rhizomatous perennial, endemic to the lower slopes of calcareous parts of the Swiss and Italian Southern Alps, in its native ground P. lutea is a plant of shaded rocks and screes (Landolt & Urbanska 1989; Grey-Wilson & Blamey 1995). In Britain and Ireland, it typically grows in the mortar of old walls and prefers half-shade. Dainty and undemanding, Yellow Corydalis has been a popular horticultural choice for walls and beds in shady corners of gardens in the British Isles since the end of the 16th century (Grey-Wilson 1989). The only problem with the plant is its ability once established to seed itself prolifically or indeed excessively and become a weedy nuisance (Hansen & Stahl 1993).

Fermanagh occurrence

This conspicuous garden escape has been recorded just six times in Fermanagh and only twice in the past 50 years – the last observation having been made by RHN in 1989. The details of the other five Fermanagh records are as follows – the first four being made by Meikle and co-workers, the last two by RHN: on west bridge, Enniskillen town, 1946; ruined house near Sand Lough, 1949; bridge between Belcoo and Blacklion, 1952; waste ground beside Ballycassidy River, 100 m N of road bridge, 9 May 1988, RHN; wall of old Railway Station, Maguiresbridge, 3 September 1989, RHN.

Flowering

P. lutea has an extremely prolonged flowering period (March to November). The flower is self-compatible and is pollinated by bees (Jonsell et al. 2001). Initially the flower is closed, and it opens with a once-only 'explosive' mechanism, similar to that of Gorse, Broom and other members of the Pea family. All of these plants are pollinated by vigorous bees of sufficient weight to trigger the flower opening mechanism (Proctor & Yeo 1973, Fig. 58, p. 205).

Seed and dispersal

The seed of P. lutea is rather too large and heavy to be readily wind-borne, but it has an attached white elaiosome oil food body which attracts ants and possibly birds. This probably explains how it manages to colonise walls (and cliffs in its native area), at heights well above ground level (Salisbury 1964). Ridley (1930) noted it growing approximately 5 m up a wall, and he suggested that ants were responsible for transporting the seed!

Fossil record

I am not aware of any fossil record for this species. I believe that there are very few fossil records for the related Fumaria species, some only at the generic level, and most or all of the records are associated with sites of human settlement or cultivation (Godwin 1975).

British occurrence

In England and Wales, P. lutea is fairly widespread and commonly naturalised S of a line between Carlisle and Berwick-upon-Tweed. However, N of this region Yellow Corydalis becomes somewhat more coastal and diffuse, except around the Edinburgh conurbation where it is again more frequent. Since the 1962 BSBI Atlas, P. lutea has increased in some areas in Great Britain (calculated Change Index = + 0.59), eg in Wales and SW England (P.J. Wilson, in: Preston et al. 2002).

Irish occurrence

The New Atlas shows the species in Ireland is very much more rare and widely dispersed than in Britain, but as with Papaver somniferum (Opium Poppy), in N Ireland it appears somewhat more frequent, although still decidedly sparse (Preston et al. 2002). Between them the Irish Flora Census Catalogue 2nd edition and Reynolds's list of alien plants Cat Alien Pl Ir indicate that P. lutea has been recorded at least once from a total of 18 Irish VCs (excluding Fermanagh, which has not had records published until now). The great majority of the Irish P. lutea records emanate from the north. I believe that this scattered pattern of occurrence simply reflects the greater number of recorder hours spent per hexad in the northern part of the island, since this level of recording enables casual species and infrequent garden escapes to be discovered along with the more common plant species.

European occurrence

In W Europe, P. lutea is widely naturalised beyond its narrow endemic range, but apart from near Narbonne in S France, it is completely absent from the Mediterranean, as well as from the entire Iberian Peninsula. Yellow Corydalis is better represented in Scandinavia than shown by Jalas & Suominen (1991, Map 2059) and, indeed, Jonsell et al. (2001) records that it is spreading northwards in coastal areas of both Norway and Sweden where it was first recorded as late as 1922.

Names

The genus name 'Pseudofumaria' combines the Greek 'pseudo' meaning 'false' and the genus name 'Fumaria', which is ultimately derived from the Mediaeval Latin 'fumus terrae', meaning 'smoke of the earth', ie arising from the ground like smoke. This is considered a reference to the diffuse foliage of some species of the genus (Gilbert-Carter 1964; Hyam & Pankhurst 1995). The Latin specific epithet 'lutea' means 'yellow', being derived from 'lutum', the ancient name of Reseda luteola (Weld), which produces a yellow dye (Gilbert-Carter 1964).

Threats

None.