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Berula erecta (Huds.) Coville, Lesser Water-parsnip

Account Summary

Native, rare or occasional and rather local. European temperate, but also considered native in W & C Asia & N America; introduced in several parts of Africa and in Australia.

1806; Scott, Prof R.; Co Fermanagh.

June to September.

Growth form, identification and preferred habitats

An always lowland, glabrous, rhizomatous and stoloniferous aquatic perennial, B. erecta is very variable in vegetative form and it is rather similar in both its simply pinnate leaf and its habitat to two other locally well represented umbellifer species, facts which could give rise to some under-recording of it. The species with which B. erecta might be confused are Sium latifolium (Great Water-parsnip) and the morphologically very variable Apium nodiflorum (Fool's-water-cress). B. erecta is by far the scarcest of the three in Fermanagh, their comparative tetrad representation being – Berula erecta 17, Sium latifolium 66 and Apium nodiflorum 120.

Overall, B. erecta is around 100 cm in maximum height, with leaves that are intermediate in size between S. latifolium and A. nodiflorum. The leaves, with 4-9 pairs of leaflets, are a dull, bluish- or yellowish-green in colour, with narrower, more irregularly toothed divisions than the other two species (Tutin 1980), although this in fact is another rather variable character in B. erecta! Submerged leaves are similar to aerial leaves, unlike those of S. latifolium. The presence on the leaf stalk of a discoloured 'ring-mark' or septum, some distance below the lowest pair of leaflets (which are sometimes quite rudimentary), is diagnostic in separating vegetative specimens of B. erecta from A. nodiflorum (Wigginton & Graham 1981). The BSBI Plant Crib 1998 (pp. 220-1), tabulates and illustrates several distinctive differences which, taken together, allow ready separation of these three similar umbellifers (Rich & Jermy 1998).

B. erecta is typically found in full sun or moderate degrees of shade,

either as an emergent on the damp margins or shallow waters around, lakes, ponds and ditches, or else submerged or emergent in seasonally flooded ground beside fast or slower running water in streams and rivers. It prefers fertile, nutrient-rich, calcareous or near neutral, eutrophic or sometimes mesotrophic environments, and fine to medium textured, organic mud or clay soils, habitat conditions which in Co Fermanagh are frequently provided by the long, dissected shoreline of Upper Lough Erne and the banks of the River Finn, localities where it has most often been found (Haslam et al. 1975; Preston & Croft 1997).

Vegetative and flowering reproduction

B. erecta has a short basal rhizome, 2-10 mm thick, with stolons arising at the lowermost nodes at the base of the hollow stem. Local vegetative spread is commonly achieved in the spring by growth of the short-lived stolons or longer surviving rhizome. Small plantlets formed in this manner, together with vegetative fragments of the plant can become detached and float off to colonise fresh sites in the water system.

Little or nothing is known of the frequency or success of seed reproduction by the species, but terrestrial and emergent plants certainly flower better and submerged ones very often fail to do so (Preston & Croft 1997). In Scandinavia (Denmark, S Norway and S Sweden), when growing in water, B. erecta has been observed to produce large, sterile populations (Jonsell & Karlsson 2010). The English Centre for Ecology & Hydrology has issued an advice leaflet for the control of B. erecta as a nuisance aquatic weed. Mechanical cutting or strimming gives only temporary respite and chemical control is recommended (https://www.researchgate.net/publication/234111350_CEH_Information_Sheet_18_Berula_erecta_water_parsnip, accessed 20 November 2021).

If it occurs at all, flowering of B. erecta takes place from July to September. The compound umbel contains 7-17 rays and is subtended by 4-7 bracts that sometimes are leaf-like. Each ultimate umbel (umbellule) contains 14-22 white flowers that are not or slightly irregular (zygomorphic) and the petals are emarginated (ie notched at their tip). The fruit is ± orbicular, 1.3-2.0 mm, somewhat compressed laterally and a dark greyish-brown in colour. The mericarps bear small indistinct ridges and, like the fruits of S. latifolium, they are adapted to water dispersal, their cells having large air-filled spaces within them that enable flotation (Sell & Murrell 2009; Jonsell & Karlsson 2010).

Toxicity

The rhizome and creeping stolons are poisonous, but not especially so, to most stock animals (Grieve 1931, p. 617; Cooper & Johnson 1998). The entry for Berula in The plant book (Mabberley 1997) has it that it proved fatal for cattle in New South Wales, Australia.

Fermanagh occurrence

B. erecta was one of the very first flowering plants recorded in Co Fermanagh by Prof Robert Scott in a list dated 1806. Although there are a total of 43 records in 17 tetrads for this species in the Fermanagh Flora Database, 15 of the squares with post-1975 dates, only two sites have been found by the RHN and the current author (RSF). These finds were at Tully Castle (the only site for the species on Lower Lough Erne), where RHN found it in July 1990, and on the shore of Derrymacrow Lough, July 2002, when RHN & RSF were accompanied by J.S. Faulkner and I. McNeill. Thus B. erecta is definitely regarded as a rare or only very occasional species in Fermanagh. The tetrad map shows that apart from the Tully Castle site, B. erecta is almost confined to Upper Lough Erne, but in terms of frequency it is very much concentrated in the far SE of this wetland area, centred around Drummully Td and Wattle Bridge near Crom and the entrance to the Old Ulster Canal.

Irish occurrence

B. erecta has declined considerably since the mid-18th century in NE Ireland (FNEI 2; FNEI 3). In NI, it is now found mainly in the Lecale area of Co Down (H38) and local and sparingly along the Newry Canal in Cos Down (H38) and Armagh (H37). There is a similar sparse presence around Lough Neagh and Upper Lough Erne, but it is rare and extremely thinly scattered or absent elsewhere in NI (Flora of Lough Neagh). In the RoI, B. erecta is quite frequent in the E & C and occasional elsewhere. It is very much more frequent and widespread in the RoI in comparison with north of the island (An Irish Flora 1996; New Atlas).

British occurrence

Despite a known decline in Britain since around 1950, presumably due to drainage and habitat destruction, B. erecta remains fairly common, widespread and stable in most of England south of a line between Lancaster and Hull. However, it is rare in SW England, Wales and Scotland, becoming increasingly coastal in all these regions (M. Southam, in: Preston et al. 2002).

European and world occurrence

B. erecta is native and widespread across Europe from being local in the southern tip of both Norway and Sweden, then widely present in Denmark, the distribution continues southwards to S Spain and east to N Greece. Although less frequent in the Mediterranean basin, it has been recorded in Corsica, Sardinia and Sicily as well as throughout Italy. It is also present in Turkey, the Middle East, Egypt and Ethiopia, and it stretches onward into W & C Asia. It is also indigenous and widespread in temperate N America and has been introduced in Australia (Hultén & Fries 1986, Map 1397).

Names

The genus name 'Berula' is a plant name mentioned by Marcellus Empiricus (Gilbert-Carter 1964) that has been borrowed, recycled and reapplied to this plant when it was reclassified and removed from the genus Sium. Marcellus Empiricus is a shadowy figure also known as Marcellus Burdigalensis (meaning 'Marcellus of Bordeaux'), who was a French, or Gaullish, herbal writer at the end of the 4th and beginning of the 5th centuries. His only extant work is the Latin book, De medicamentis, a typical herbal pharmacology which drew on the work of many earlier medical and scientific writers including Pliny the elder, as well as on popular folklore remedies and magic of the time (Sharpe 1964). As such, 'Berula' is another example of a 'book name', more or less chosen at random to act as a label. The specific epithet 'erecta' is too obvious to translate, but the growth of the plant can be quite sprawling, not always erect.

The English common name 'Lesser Water-parsnip' simply informs the student that the plant is somewhat smaller than the similar Great Water-parsnip (Sium latifolium) and neither plant has the root qualifications to make it a parsnip.

Threats

None.