This site and its content are under development.

Aethusa cynapium L., Fool's Parsley

Account Summary

Introduction, possibly an archaeophyte, declining and now very rare. European temperate, an introduced weed in both N Europe and N America.

1892; Praeger, R.Ll.; cultivated field by the Ballycassidy River.

Few recording dates with months, but mainly July.

Growth form and preferred habitats

A ruderal annual or biennial, glabrous herb, very variable in size and many other characters, A. cynapium has smooth, thin, dark green, finely dissected leaves that give off a distinctive acrid, unpleasant odour when bruised, totally unlike the familiar, culinary Garden Parsley (Petroselinum crispum). The most characteristic distinguishing feature of the plant when in flower is the downwardly directed, strongly reflexed bracteoles beneath the smaller umbels of white flowers. They are usually three in number, but can be four or five (Salisbury 1964; Jonsell & Karlsson 2010).

A. cynapium is chiefly a weed of lowland, arable and disturbed ground, neglected, often boundary waste areas, hedge banks and gardens. Less commonly, it is found on river-banks and in poached, heavily trampled pastures and around gateways. It generally prefers more basic or lime-rich, sandy or loamy, cultivated or disturbed soils and sunny, warm ground situations. The established strategy of the species is categorised as R/CR (ie intermediate between Ruderal and Competitive-Ruderal) by Grime et al. (1988, 2007).

Flowering reproduction

Small, white, bisexual flowers are produced June to August, the ultimate umbel divisions, uniquely 3-bracted; after pollination by flies and bees of various sorts, the typical sized garden form of this weed may produce up to 3,000 green, oval, flat, heavily ribbed fruits, which split in two before their release (Salisbury 1964). Germination can occur in autumn or, more commonly, in the spring. As is often the case, and especially so in this family, little or nothing is known about its real powers of dispersal, but in the past it has certainly been regularly (frequently) transported by agricultural man as a contaminant of commercial crop and pasture seed.

Many references regard it as long-persistent in the soil seed bank, surviving burial for five or more years (Thompson et al. 1997).

Variation

In Britain, where the species is still widespread in the lowlands, the plant is very variable and sufficiently polymorphic for four subspecies to be recognised, although they are not always separated by field botanists. The most common form, subsp. cynapium occurs throughout the range of the species, while the dwarfish subsp. agrestis (Wallr.) Dorstál., which is very probably an archaeophyte, is most frequent on arable land in S England, since it can escape the reaper thanks to its reproductive shoots being shorter than the crop stubble (Salisbury 1964; Tutin 1980; M. Southam, in: Preston et al. 2002).

Two additional taxa, sometimes considered varieties of subsp. cynapium (Stace 2019), are subsp. gigantea (Lej.) P.D. Sell, annual, stem 100-200 cm, bracteoles 1-2 times as long as partial umbels, and subsp. cynapioides (M. Bieb.) Arcang., biennial, 100-200 cm, bracteoles 2-3(-4) times as long as partial umbels (Sell & Murrell 2009).

Toxicity

A. cynapium is a very poisonous plant, but the polyacetylene toxins it contains (conine and cynapine) are a danger to livestock only when it is eaten fresh and in large quantity. Fortunately, the plant gives off a repulsive warning odour, sometimes described as acrid and mouse-like (the genus name derives from the Greek 'aitho', 'I burn'). The stink increases the more the tissues are bruised, readily discouraging humans from consuming it (Salisbury 1964, p. 289).

That said, however, the finely dissected, darkish, blue-green leaves can be mistaken for Parsley, and the roots for Radish. Symptoms of poisoning by this species include nausea, vomiting, diarrhoea and muscular tremors (Cooper & Johnson 1998).

Fermanagh occurrence

There are just six records in total for A. cynapium in the Fermanagh Flora Database. There is only one recent record, from July 2000, which was observed by RHN in disturbed conditions on the roadside N of Killymackan. Apart from this, Fool's Parsley had not been recorded in the VC for almost half a century.

As listed above, the first record of A. cynapium in Fermanagh was made by Praeger, at the end of the 19th century, and Meikle and his co-workers added four more stations during the 1946-53 period of their recording activity. The details of these latter records are: Lisbellaw, 1946-53; quarry near Donagh Crossroads, 1946-53; weed in garden of Melvin Hotel, Garrison, 1949; and in cultivated ground, Belcoo, 1952.

A. cynapium also appears to be a declining weed in NE Ireland where it was once a frequent species. FNEI 3 recorded very few sightings since 1920 in Cos Down (H38), Antrim (H39) and Londonderry (H40). Having said this, the absence of new data may be a matter of effort or direction in recording; Beesley (2006) has listed seven additional weedy sites in Co Antrim (H39), all with post-1989 dates.

Irish occurrence

Probably mainly for the mentioned soil, weather and arable farming associations, A. cynapium is largely a southern and eastern species in Ireland, the distribution and frequency thinning very noticeably towards both the W and N, where damp, acidic pasture grasslands or peat bogs heavily predominate in the landscape and arable agriculture has become of rare occurrence.

British and Irish status

Aside from the above subspecies distinction, in Britain A. cynapium is regarded as native as far north as Edinburgh and Glasgow. North of this, however, plus on the Isle of Man and throughout Ireland, Fool's Parsley is everywhere considered a definite or very probable introduction (Scannell & Synnott 1987). The current post-glacial fossil record shows A. cynapium first appearing late in the current interglacial (in Britain, the Flandrian, in Ireland, the Littletonian) at zone VI and, subsequent to this, at archaeological sites: a single record in the Bronze Age, followed by two appearances in the Iron Age and three in the Roman period. Godwin (1975) comments, "In the British Isles too, it becomes less frequent in Ireland, and much less so in Scotland, a pattern seen in other Umbelliferae with a late Flandrian expansion and response to anthropogenic influence." RHN and the current author (RSF) believe this weed species most probably is an ancient agricultural introduction throughout B & I.

European and world occurrence

A. cynapium probably originated in C Europe, but it is now widespread in temperate Eurasia and N Africa. Man has certainly been instrumental in its spread as a weed of cultivation, both in N Europe and N America (Hultén & Fries 1986, Map 1403).

Threats

None.