Viola tricolor L. subsp. curtisii (E. Forst.) Syme, Seaside Pansy
Account Summary
Native, very rare and almost certainly extinct, but also possibly a mis-identification. Suboceanic temperate.
1884; Barrington, R.M.; Tully South Td, SW of Lisnaskea, Upper Lough Erne shore.
There is only one 1884 record for this mainly coastal subspecies and it may have been a misidentification, although Barrington says of his record, "This species [sic] has been named by Professor Babington.", proving that he had a verified voucher specimen. We do not know what became of this specimen, however.
Circumstantial support for this inland record of a normally maritime species comes from several other similar occurrences in Fermanagh, including Carex distans (Distant Sedge), Plantago maritima (Sea Plantain), Asplenium marinum (Sea Spleenwort) and Bolboschoenus maritimus (Sea Club-rush).
Additional support comes from the fact that V. tricolor subsp. curtisii also occurs around Lough Neagh with an assemblage of otherwise almost exclusively maritime species (FNEI 2; Flora of Lough Neagh). Nevertheless, and despite this, in the Revised Typescript Flora, R.D. Meikle wrote of it, "... should probably be referred to V. tricolor, true V. curtisii has not been seen in Co Fermanagh".
Growth form and preferred habitats
This attractive little annual violet is a casual ruderal species of disturbed, sparsely vegetated, dry or well-drained, light, sandy acid or neutral ground in pastures, banks, quarries and stony or sandy lakeshores. Unlike the closely related and rather similar V. arvensis (Field Pansy), it avoids calcareous soils. Although very variable, V. tricolor is recognised by its deeply lobed stipules, the mid-lobe narrowly elliptic to oblanceolate, ± flat-faced flowers (several produced per stem between April and September), with individual petals not more than 12 mm long. The typical blossom is a mix of violet, blue, cream and yellow colours, some yellow usually being present. Plants have erect, often branched stems from a short (or sometimes absent) rhizome and the habit ranges from lax and sprawling to compact (Parnell & Curtis 2012; Porter & Foley 2017).
Elsewhere in B & I, Wild Pansy is regarded primarily as a native herb of dunes, acid heaths and hillsides, all presumably well-drained, mainly open, grassland habitats.
Variation
The species aggregate V. tricolor is very variable and includes perennial forms. Petal size and colour vary most conspicuously with development and with season. Petals are small, relatively wide and whitish or pale coloured at the beginning of the flowering season, but they almost double in size, elongate and become increasingly intense in colour over several days until the flower is fully developed. Later in the season, individual plants frequently produce smaller, narrower and less colourful flowers than those of early summer. As the species name suggests, flowers are often two or three coloured from a shade palette ranging from violet and sky-blue to cream and yellow. Although entirely violet flowers are also quite frequent, pure creamy-white or completely pale yellow ones are much rarer. Studies show there is not any obvious geographical or ecological pattern to the flower variation (Jonsell et al. 2010).
Variation in plant habit is more significant than in the flower in this case. Coastal plants and those from sandy soils are usually perennial, rather than the annuals found elsewhere. When sand blows over the lower stems of the perennials, they root and produce much-branched subterranean or procumbent growth that can eventually develop large clonal colonies. This form of the plant, which maintains its features in cultivation, is widespread around the coasts of Scotland, Wales & Ireland, but much more occasional and scattered along English coasts. It is described by Jonsell et al. (2010) and Porter & Foley (2017) as a sandy ecotype, although previously it was very often recognised as subsp. curtisii. Indeed, examination of the BSBI Big Database (accessed 2 January 2020), shows it remains a subspecies in that forum. What some regarded as 'true' subsp. curtsii (E. Forst.) Syme is now considered very much rarer and it may indeed be endemic to its original English station, Braunton Burrows in N. Devon (VC 4), and to some sandy heaths in Breckland, East Anglia (VC 26 & 28) (Porter & Foley 2017). The variation pattern here and elsewhere over the whole species range needs further study to clarify the taxonomy of these forms.
Hybrids
Three hybrids involving V. tricolor are known, one of which is extremely rare in Britain and has not been recorded in Ireland at all (V. lutea Huds. × V. tricolor L.). More commonly, V. tricolor hybridises with V. arvensis Murray to form V. × contempta Jord., but while this is widely recorded, if scattered across much of Britain, it has only been found once in midland Ireland. The third hybrid is the extremely variable Garden Pansy (V. × wittrockiana Gams ex Kappert), which is the product of three violet species, V. lutea, V. tricolor and V. altaica Ker Gawl. This has over 400 named garden varieties and is very frequent and widely recorded in Britain, but much less so in Ireland, rare in the north of the island and never recorded in Fermanagh (Stace et al. 2015).
Status in Britain
V. tricolor is regarded as indigenous in Britain on the basis of the fossil evidence of a long pre-agricultural presence (Godwin 1975, p. 138). Changed land use, intensive agriculture from the 1950s onwards, herbicides and, locally in Fermanagh, a major decline in arable cultivation, have produced a widespread decline of V. tricolor during the 40 years between the two BSBI atlases (Walters & Perring 1962; Preston et al. 2002). This decline is most marked in SE England but has happened throughout B & I. As a result, V. tricolor has nowadays been pushed into an increasingly restricted, occasional, ruderal role, as an early colonist of open vegetation associated with disturbed situations in artificial man-made habitats. These include cultivated ground, thin patchy garden lawns, waste places and other temporary, dry, disturbed growing conditions near habitation (M.S. Porter & M.J.Y. Foley, in: Preston et al. 2002).
In Ireland, V. tricolor subsp. tricolor has always been chiefly a plant of northern regions, associated with arable cultivation (An Irish Flora 1996). It remains widespread but rare and declining in this role, principally found nowadays around the Lough Neagh basin (M.S. Porter & M.J.Y. Foley, in: Preston et al. 2002; Day & Hackney 2004). Like other Viola species, it seeds prolifically and it can survive dormant in the soil seed bank for prolonged periods, perhaps for many decades. Thus it cannot be written off as locally extinct until a very long time after its last sighting (Thompson et al. 1997).
Fermanagh occurrence
While V. tricolor subsp. tricolor has been recorded in 17 Fermanagh tetrads, 3.2% of those in the VC, the only place in the county where we can rely on regularly finding it is in the disused sand pit at Pubble near Tempo. Twelve of the 27 records in the Fermanagh Flora Database are pre-1975 and, apart from the Pubble sand pit, since 1975 it has only been seen at ten other disturbed or urban sites thinly scattered around the VC. It is, however, still perfectly capable of reappearing from the soil seed bank, whenever and wherever growing conditions prove favourable.
European and world occurrence
In continental Europe, V. tricolor s.l. occurs from Iceland and Scandinavia southwards to the northern shores of the Mediterranean and eastwards through Turkey to the Ural and Caucasus mountains. In Scandinavia, V. tricolor is regarded as native or an archaeophyte in the south and west, but in the north and east it is considered a neophyte and often is merely casual in its occurrence (Jonsell et al. 2010). It also occurs in the mountains of NW Africa and has spread with cultivation and settlement to become naturalised in parts of SW Asia (including India and the Philippines), N America (mainly in eastern states) and in New Zealand (Hultén & Fries 1986, Map 1337).
Threats
Changing land use and agricultural intensification.