Pulicaria dysenterica (L.) Bernh., Common Fleabane

Account Summary

Growth form and preferred habitats

Pulicaria dysenterica is a late-flowering, woolly or cottony-coated perennial, 20-40(-60) cm tall, with a creeping, scaly, underground rhizome or rootstock that sends up shoots at intervals, thus forming its characteristic, persistent, clonal patches. It can also produce surface-running stolons from the rhizome or rootstock, which assist in patch-formation. The white-woolly stems branch above and are thickly set with sessile, narrow, oblong-lanceolate, toothed, softly hairy, sinuate leaves that clasp the stem at their bases (Melderis & Bangerter 1955; Butcher 1961; Sell & Murrell 2006).

This is a very frequent lowland, waterside plant of damp, open areas on roadside verges, wet meadows, marshes and fens on the sides of ditches, streams, rivers and lakes, including tall-herb fens that are subject to sufficient disturbance to keep the habitat open (Garrard & Streeter 1983). It also frequents damp coastal habitats including sand-dune slacks and seepage areas on sea cliff ledges. It occurs on a wide range of soil types, from base-rich to acidic, but appears to prefer nutrient-rich ground where there is a measure of disturbance (G. Halliday, in: Preston et al. 2002; G. Halliday & K.J. Walker, in: Stroh et al. 2023).

The established strategy of P. dysenterica is categorised as C/CSR, meaning it is intermediate between a straightforward Competitive species and one that is a more balanced mix of all three plant strategies, Competitor, Stress-tolerator and Ruderal (Grime et al. 1988, 2007).

Flowering reproduction

Flowering takes place rather late in the growing season, from late July or early August to late September. Usually three or a few more yellow flowerheads, 2.5-4.0 cm in diameter, are arranged in a terminal, ± flat-topped corymb (or cymose panicle), on erect, branching stems (Butcher 1961). The involucral bracts are bristle-like (filiform) and densely hairy or woolly. The flowerheads contain flowers of two types: numerous (up to 100), narrow, yellow, spreading ray female ones, and very many central, stronger yellow, bisexual, tubular florets (up to 600 in large heads) (Hutchinson 1972). The current author (RSF) prefers the older English common name 'Yellow Fleabane', since it emphasises the bright, showy, attractive colour of the flowerheads which are large in relation to the size of the plant. They are visited by a wide range of insects, but the florets are pollinated mainly by flies (Clapham et al. 1987). The air-borne achene fruits, 1.2 × 0.5 mm, narrowly ovoid, ribbed and hairy are crowned with a pappus of two rows of hairs; the inner row of long silky hairs clearly assisting dispersal flight, while the outer row consists of a ring of short scales joined into a cup, which looks more or less toothed along its rim (Butcher 1961; Clapham et al. 1987).

The current author has not located any statistics for seed production or dispersal distances, and since the plant possesses a creeping rhizome or rootstock and it also produces spreading stolons that allows clumps to develop, vegetative reproduction is obviously significant in survival and, given suitable open, moist growing conditions, lateral extension to form patches. Nevertheless, there does not appear to be any readily available information regarding the reproductive capacity of the species, something that ought to be addressed, especially now that the plant appears to be spreading in B & I (see below).

The survey of the soil seed banks of NW Europe contains just two estimates for P. dysenterica, one categorising it as transient (surviving less than one year), while the other describes it as short-term persistent, ie surviving between one and five years (Thompson et al. 1997).

Fermanagh occurrence

Common or Yellow Fleabane is locally frequent and forms clonal patches in damp or wet, marshy, relatively open grassland, fen ditches and roadsides around both Upper and Lower Lough Erne. However, as the tetrad distribution map demonstrates, it is much scarcer and thinly scattered elsewhere in the county. The species is recorded in 70 Fermanagh tetrads, 13.3% of those in the VC, but only 62 of these have post-1975 records.

British and Irish occurrence

P. dysenterica has been recorded at least once in every Irish VC (Cen Cat Fl Ir 2), yet despite this, the mapped distribution in the New Atlas hectad map appeared very patchy all across the country. The hectad map in the Atlas 2020 shows the species has spread considerably in the last few decades, and it is now much more widespread in Ireland, although remaining decidedly scarce in parts of the N & W.

Likewise, in Britain, Common or Yellow Fleabane previously had a definite southern distribution, becoming very scarce and more coastal northwards of a line between Lancaster and Hull. In the New Atlas map published in 2002, it was shown as rare and almost entirely coastal from N England and Scotland, but the Atlas 2020 map now shows it has spread considerably in recent years and while still very thinly scattered in most of Scotland, it has been recorded right to the very far north of mainland Scotland in Caithness (VC 109) and has also been found on the Outer Hebrides (VC 110) (Stroh et al. 2023).

In both B & I, the observed increase and wider distribution of P. dysenterica is likely due to a combination of more active, intensive and better directed botanical recording by BSBI members and the greater occurrence in recent years of disturbed, nutrient-enriched ground associated with human activities (G. Halliday & K.J. Walker, in: Stroh et al. 2023).

European and world occurrence

P. dysenterica belongs to the Eurosiberian southern-temperate phytogeographical element. It is widespread in W, S, C and SE Europe and adjacent NW Africa, reaching its northern limit as a native species in SE Denmark. It has been introduced northwards into S Scandinavia. In the south of its range, it stretches eastwards into Turkey and Asia Minor, the Caucasus and beyond into C Asia, almost as far as the Himalaya. In some of this eastern extension, it may well be introduced, as is also the case in S Africa and eastern N America, where it is very rare (Hultén & Fries 1986, Map 1795).

Uses

As both the botanical and common names suggest, P. dysenterica has traditionally had medicinal properties and has been cultivated therefore by herbalists. Linnaeus gave the Latin specific name because in his time (the 1730s-1770s), it was considered a cure for dysentery. The sap of the plant is described as bitter, astringent, aromatic, mucilaginous and salty, and animals refuse to eat it. The leaves when bruised give off a somewhat soap-like, carbolic odour that is reminiscent of both cats and Chrysanthemums (Mabey 1977). The medicinal properties claimed are probably associated with the astringent sap which gives off an obnoxious, pungent smell that deters even insects. The plant was collected and burnt as a fumigant, reputed to drive off midges and fleas. It was formerly also used to treat skin itches and other cutaneous disorders (Grieve 1931).

While Grieve is quite reticent and unenthusiastic regarding the usefulness of the species as a medicinal herb, Allen & Hatfield (2004) are much more dismissive of it, regarding the two supposed uses of the plant as, "suspiciously like hand-downs from book learning". They also describe and write it off as, "a marginal interloper as far as the folk tradition was concerned".

Names

The generic name 'Pulicaria' is derived from the Latin 'pulex', meaning 'flea' (Hyam & Pankhurst 1995), from the fact that in the past the plant was used as a fumigant, and hence the English common name, 'Fleabane' (Grieve 1931). Another of its English common names is 'Harvest flower', since it blossoms in August and September (Grigson 1955, 1987).

Threats

None.

References

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