Veronica scutellata L., Marsh Speedwell
Account Summary
Native, frequent. Eurosiberian boreo-temperate, but also in N America and widely naturalised beyond its native range.
1881-2; Barrington, R.M.; Devenish Island, Lower Lough Erne.
April to October.
Growth form, recognition and preferred habitats
Marsh Speedwell is a small, slender, creeping, semi-recumbent, straggling, ascending perennial the stems of which root at the lower nodes. It bears narrow, opposite, lanceolate, stalkless leaves that slightly clasp the stem. The leaf margins appear almost entire, but closer examination shows they possess very minute, distantly spaced teeth. Plants are usually hairless, but occasional hairy forms are known to occur, especially in rather drier habitats, and have been named var. villosa Schumach (Clapham et al. 1987; Sell & Murrell 2007).
Marsh Speedwell produces alternate, very loose, few-flowered raceme inflorescences of small, whitish, pinkish or pale blue flowers borne on long, slender stalks (Perring et al. 1989). It is readily distinguished from V. catenata (Pink Water-speedwell) and V. anagallis-aquatica (Blue Water-speedwell) with which it might be confused, in having its usually rather few-flowered inflorescences arranged alternately on the stem, ie only a single inflorescence is produced from each pair of leaves at a stem node. The linear-lanceolate leaves are often reddish brown to dark bronze due to the presence of anthocyanin pigments and the petals vary from pale lilac, to pink to almost white, striped with darker veins.
Marsh Speedwell is found in a wide range of wetland habitats including in still or slow-moving waters on the shallow margins of smaller lakes, ponds, pools and ditches, and in moist to damp, poorly drained, often winter-flooded marshy places in wet meadows, fens, peat bogs, wet heaths and hillside flushes, usually on rather infertile, acidic or calcium-deficient soils (Garrard & Streeter 1983; Sinker et al. 1985; A. Horsfall, in: Preston et al. 2002). It can grow either on bare ground or among tall herb vegetation and appears tolerant of the grazing pressure and the trampling it receives from cattle in the regularly flooded water meadows around Upper Lough Erne. The species reaches its highest site in B & I at Cross Fell at 780 m (A. Horsfall, in: Preston et al. 2002).
Climbing ability
V. scutellata creeps at the base, but can ascend to 50 cm or more in height when drawn up by taller herbaceous vegetation around it. Species like V. scutellata, with very slender stems ascending from a creeping or procumbent base, do not have the photosynthetic reserves and physical ability to stand erect by themselves, so they make use of their better equipped neighbours to prop themselves up and enable them to climb towards the light. The least specialised method of climbing is achieved by plants that weave their leaves and stems in and around the neighbouring plants they are using as props. At its simplest, this can be achieved by the climbing plant developing rigidly horizontal leaves. In Marsh Speedwell, the leaves are initially vertical and so can be pushed through gaps in the foliage of their neighbouring plants. Later on, the Veronica leaves of this and related species are held horizontally, thus anchoring the decidedly weak stems in position at a greater height than would otherwise be possible (Fitter 1987, p. 192).
The established strategy of V. scutellata is categorised as R/CSR meaning it is intermediate between a straightforward Ruderal and a more balanced mix of the traits of the three main strategies, Competitor, Stress-tolerator and Ruderal (Grime et al. 1988, 2007).
Flowering reproduction
V. scutellata flowers from June to August. The solitary inflorescence at each node on the erect flowering stem bears relatively few, well-spaced bisexual flowers, each small blossom borne on a long, slender, thread-like flower stalk, subtended by a very much shorter linear bract. The flowers, 7-8 mm diameter, have a corolla that is usually pale blue, striped with purple lines, but they can vary in colour from pale pink to white. They attract flies as pollinators and, if not crossed, the flowers can self-pollinate (Fitter 1987). The fruit capsule, 3.5 × 4 mm, is flat and reniform (kidney-shaped) and deeply notched, veined and winged (Butcher 1961). It opens by dehiscing into two valves apically. The seeds 0.8-1.0 mm are broadly elliptical, flat, smooth and pale brown (Butcher 1961; Sell & Murrell 2007).
Seed dispersal and longevity
There does not appear to be any specialised seed dispersal mechanism or adaptation, but the seeds are light and presumably can be wafted out of the open capsule by wind passing over it. Seeds probably can also be dispersed in flowing water or may be picked up and transported in mud. V. scutellata plants have been listed among many others grazed by Arctic Reindeer feeding on the low vegetation and transporting seed internally and excreting it with their dung (Ridley 1930, p. 373). It appears likely that the species would also be transported in this way by cattle and other grazing animals.
There is some doubt as to the persistence of V. scutellata seed in the soil. The survey of soil seed banks in NW Europe contains data from nine studies, three of which considered the seed survival transient (less than one year); one study believed it short-term persistent (surviving 1-5 years); one reckoned it long-term persistent (surviving more than five years); and four recognised seed as being present in soil, but could not assign it to one of the three seed bank types (Thompson et al. 1997).
Fermanagh occurrence
In Fermanagh, V. scutellata is a frequent to local perennial around the shallow margins of water bodies and in hollows on adjacent fen water meadows on more or less acidic, poorly drained soils including peat, but unlike V. beccabunga (Brooklime) it is never present in any great quantity. The local headquarters of the plant is undoubtedly around the fen-girdled shores of Upper Lough Erne and in marshy ground around nearby lakelets and rivers. Otherwise, it is scattered and rather local in its occurrence, although in reality it has been recorded in 149 Fermanagh tetrads, 28.2% of those in the VC. Essentially, it is a species of shallow water around lakes and rivers, marshy meadows and, very rarely, by bog drains.
British and Irish occurrence
V. scutellata has been recorded from every Irish VC, but it is probably declining in some and, for instance, in the Flora of Co Dublin, it was regarded as common only in marshes in the mountainous southern district and very rare elsewhere (Doogue et al. 1998).
The New Atlas hectad map shows that V. scutellata is very widely distributed throughout B & I, but the distribution is scattered and has a definite predominance in N & W parts of both islands. In N Ireland, it appears much more consistently recorded than in the RoI, although this may simply be an artefact of recorder effort visible at the hectad scale. The New Atlas hectad map shows a definite widespread decline in the species occurrence across B & I, but especially in C & S England and C Ireland. Analysis of the map data indicates these declines have occurred since 1950 (A. Horsfall, in: Preston et al. 2002).
European and world occurrence
V. scutellata belongs to the European boreo-temperate phytogeographical element and is of frequent occurrence across most of Europe, although it becomes rare in the Mediterranean basin and is only sparsely present in N Africa. It also stretches across into N Asia and eastwards to Kamchatka (Clapham et al. 1987). Hultén & Fries (1986, Map 1648) state that it is considered native in N America and they map it as such, although they do mention that it is introduced in S America and in New Zealand.
Names
The Latin specific epithet 'scutellata' is derived from 'scutella', meaning 'a small salver or dish' or 'scutellatus', 'shield-shaped' or 'platter-like' and thus refers to something that is a small shield - or saucer-shaped feature, although exactly what this refers to is not obvious to the current author (RSF) (Gilbert-Carter 1964; Gledhill 1985; Stearn 1992).
Threats
None at present.