Montia fontana subsp. variabilis
(Walters) Kozhevn., a form of Blinks
Account Summary
Two records exist, at widely separate sites with no apparent similarity. The sites are: Drumgrenaghan shore near Lackboy, Boa Island, Lower Lough Erne; and Derrynacarbit Lough, Little Dog Forest.
Growth form and preferred habitats
This small, fleshy, annual or rarely perennial plant is readily overlooked and is very probably under-recorded in Fermanagh as also occurs elsewhere. It can grow in a great variety of permanently or seasonally wet situations, changing its habit from elongate, floating stems in streams, to terrestrial forms – either a spreading prostrate mat, or erect or tufted, cushion-like colonies. Blinks grows in wet, muddy hollows in fields, beside ditches, streams and lakeshores, or in flushes and springs on moorland. A very interesting summary account of the ecology of pioneer plants of exposed mud, including Montia (as M. chrondrosperma), was penned by Salisbury (1970).
Fermanagh occurrence
M. fontana has been recorded in 158 tetrads, 29.9% of those in the VC. The species is widely scattered throughout Fermanagh, but is mainly found in the less intensively farmed areas of the county.
Variation and taxonomy
Four subspecies or varieties are recognised by some taxonomists, being distinguished on the basis of their black seed coat surface shininess and/or its sculptured texture (Walters 1953; Stace 1991, 1997). However, the different seed types are connected by intermediates (however rare) and thus form a continuous series of gradual variation. Research in this phenotypically extremely plastic species, whose form varies with both habitat conditions and vigour of growth, has produced no additional diagnostic character(s) correlated with the seed coat patterns. Therefore, Lekkerkerk et al. (1983) concluded that formal intraspecific subdivision is not a sensible option.
In the recent Flora Nordica, 2, Jonsell et al. (2001) chose to regard one of the variants, the small erect land form with dull surfaced, tuberculate seeds as a separate species, M. minor C.C. Gmel. (= M. fontana subsp. chondrosperma (Fenzl) Walters). Otherwise, the Nordic authors treat the remaining variation as M. fontana L., without subdivision. Their taxonomic treatment appears to give heavy weighting to ecological differences, and it harks back to the situation previous to Walters’s (1953) recognition of the four seed types.
Irish occurrence
In an Irish context, the authors of An Irish Flora commented that apart from their seed coats, "there appears to be no other difference between these groups in Ireland". All four seed coat variants of M. fontana were recorded in Fermanagh by Meikle and his co-workers during the summer of 1948. However, no more recent work has been done to distinguish them and we have consistently ignored them. The records of the subspecies are listed below purely for completeness.
It is clear from the paucity of Irish records of the four 'subspecies' plotted in the BSBI's New Atlas, that the majority of Irish field botanists are not minded to distinguish Blinks at subspecific level (Preston et al. 2002).
Looking at the New Atlas hectad map of Montia fontana, the species is widely distributed in the N and the far S of Ireland, is less well represented on the W and E coasts and only thinly scattered over inland counties of the Republic of Ireland (Preston et al. 2002).
British occurrence
The New Atlas hectad map shows M. fontana is widely recorded across the entire latitudinal range of Great Britain and its associated isles, the distribution everywhere displaying a greater and more consistent presence in the N and W. As might be expected from its damp, acidic or neutral soil ecological preferences, it is less well represented in chalk and limestone areas, and from heavily populated, industrialised or intensively farmed areas of S and E England (Preston et al. 2002).