Veronica serpyllifolia L., Thyme-leaved Speedwell

Account Summary

Growth form and preferred habitats

This small, creeping perennial has hairy stems, 5-15 cm long, that lie prostrate or decumbent, rooting at the nodes, but branches are ascending, forming dense, leafy tufts of growth. Leaves are opposite, shortly stalked, blades 5-20 × 4-15 mm, leathery, broadly ovate or oblong-ovate, rounded at their apex and also at the base, margins entire or shallowly crenate, glabrous or almost so. Flowers are rather numerous in terminal leafy racemes, the subtending leaves gradually decreasing in size upwards and becoming alternate. Typically, the lower flowers are in fruit before the upper have finished (or even begun) blooming (Hutchinson 1972; Sell & Murrell 2007).

It generally appears sparse to abundant in a very wide range of open, more or less disturbed, damp, acid habitats. These include poorer grassland, grazed water meadows, fens, heaths, damp garden lawns, clearings in woods or their margins, plus any bare, damp, disturbed soil along tracks and on waste ground. The plant is tolerant of soil chemistry, moisture status, medium shade, grazing pressure and trampling. In mesic conditions, about the only thing it cannot cope with is competition from tall or vigorous, tight turf-forming grasses and herbs, since it requires more open, 'gappy' conditions than these plant associates allow (Sinker et al. 1985).

The established strategy of V. serpyllifolia is categorised as R/CSR, meaning it is intermediate between a straight Ruderal species and a more balanced mix of all three strategies, Competitor, Stress-tolerator and Ruderal (Grime et al. 1988, 2007).

Flowering reproduction

The species has a very long flowering period, almost all year round, although the main period is from March to October, and the peak lies between May and July. The small bisexual flowers, 5-10 mm in diameter, borne in lax leafy racemes, have calyx lobes linear, obtuse, glabrous, and the 4-lobed corolla, divided almost to the base is white, pale blue or bright blue, striped with darker lines (Sell & Murrell 2007). The two anthers lie close together either side of the small, capitate stigma, so that insect visitors (usually flies) may effect cross- or self-pollination (Hutchinson 1972; Garrard & Streeter 1983). Insects visiting Veronica species grasp the bases of the two stamens for support, pulling them together and, in so doing, they dust themselves and the stigma standing between them with pollen (Proctor & Yeo 1973; Hyam & Pankhurst 1995).

The fruit is a flat, somewhat rounded, notched capsule, very shortly glandular-hairy and tipped by the slender persistent style. The ripe capsule dehisces into two valves, usually apically and the flat, ovoid seeds, 0.7-0.9 mm, are pale straw-coloured (Sell & Murrell 2007).

Apart from being attached and transported in mud, seed is known to be dispersed internally by browsing animals, including cattle, horses and goats (Salisbury 1964, p. 103).

There are a total of 37 estimates of seed longevity in the soil seed bank survey of NW Europe, of which eight consider it transient (surviving one year or less), ten reckon it is short-term persistent (survives less than five years), eleven regard it as long-term persistent (surviving at least five years) and eight found seed present but could not assign it to one of the three seed bank types (Thompson et al. 1997).

Identification

The species has glabrous, almost completely untoothed leaves, prostrate, spreading stems that root at the nodes and branches bearing terminal racemes of pale blue flowers with styles 2.5 mm long that, taken together, distinguish V. serpyllifolia from both V. arvensis (Wall Speedwell) and V. officinalis (Heath Speedwell). The bracts of the flowers are longer than the pedicels, which in turn are longer than the calyx (Garrard & Streeter 1983).

Variation

V. serpyllifolia is a rather variable plant of which at least 20 variations have been described (Hultén 1974). Two subspecies occur in B & I, but as elsewhere in Ireland, only the more common form, V. serpyllifolia subsp. serpyllifolia, has been found in Fermanagh, and most recorders do not work at the subspecific rank. The other subspecies, subsp. humifusa (Dicks.) Syme is an arctic-montane form that belongs to the discontinuous circumpolar plants (Hultén 1974, p. 260 & Map 252). It has rooting stems and broader, almost entire leaves and larger, bluer flowers. In Britain, it is a scarce plant of damp places in mountains (Garrard & Streeter 1983).

Fermanagh occurrence

V. serpyllifolia is very common and widespread, occurring in 346 Fermanagh tetrads, 65.5% of those in the VC.

British and Irish occurrence

Widespread and common throughout B & I, the New Atlas hectad map showing V. serpyllifolia is almost omnipresent in lowland Britain and at altitudes of up to around 825 m. The distribution is stable, but thins somewhat to the N & W in Scotland where wetter, more acidic peatlands predominate. In Ireland, the picture is similar, the distribution almost complete at the hectad level of discrimination, but thinning in the Central Plain and in the western coastal region, where very wet, strongly acidic peatlands become the dominant vegetation under a hyper-oceanic climate regime (A. Horsfall, in: Preston et al. 2002).

European and world occurrence

V. serpyllifolia subsp. serpyllifolia originated in the temperate part of Eurasia, from where it has spread northwards as a weed throughout almost all of Europe, from Iceland to Scandinavia (71°N) and south to C Spain and Portugal, Sicily, Albania and Thrace. It is also present in the mountains of N Africa and has been spread as a weed to many areas around the globe, including N & S America (both E & W USA), E Asia, Australia, New Zealand, Madeira, the Azores and Canary Islands, Tristan da Cunha and St Helena, S Greenland and doubtless in other places in its present range (Hultén 1974, Map 251; Hultén & Fries 1986, Map 1640; Clapham et al. 1987).

Names

The origin of the genus name 'Veronica' is problematic. It may be named in memory of St Veronica, who the myth has it, wiped the sweat from Christ's face (Gilbert-Carter 1964; Gledhill 1985). Alternatively, some authorities give it as a corruption of 'Betonica', plants of the two genera having some degree of similarity in their leaves. Other suggestions are that the name is a Latin form of the Greek word 'Beronike', or else refer it to the Greek 'hiera eicon', meaning 'sacred image', or the Arabic 'viroo nikoo', 'beautiful remembrance' (Johnson & Smith 1946). In truth, the origin or derivation is unknown.

The Latin specific epithet 'serpyllifolia' translates as 'Thyme-leaved' (Gledhill 1985), or (better) 'with leaves like Thymus serpyllum' (Stearn 1992).

The English common name 'Speedwell' was first recorded for V. officinalis at the end of the 16th century by Lyte (1578) but since then its use has been extended to numerous (or all) other species of the genus (Britten & Holland 1886). The healing medicinal properties of the genus Veronica were linked to Wales by Gerard (1597, 1633), where he said it was known by the name 'Fluellen'. He went on to create confusion by extending this Welsh name to other Veronica species and to two British species of another genus, Kickxia, as well (Grigson 1974; Allen & Hatfield 2004).The meaning or 'sense' for a medicinal plant means 'prosper well', or 'go on well' or just 'get well soon'. V. officinalis was regarded as a significant strengthening and wound-healing herb, also said to be good for treating coughs (Grigson 1974).

Threats

None.

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