Veronica agrestis L., Green Field-speedwell

Account Summary

Growth form, identification and preferred habitats

A small, 10 cm tall, much-branched, spring germinating, summer annual that flowers throughout the whole year (although mainly April to September), V. agrestis was once, but is no longer, a common, locally abundant, ruderal weed of cultivated ground and arable crops across lowland B & I. Nowadays, it is rare and mainly seen in gardens and on waste tips where garden rubbish is discarded. It is especially characteristic of dry disturbed soils and its established strategy was categorised as R/SR, meaning intermediate between a straight Ruderal and a Stress-tolerant Ruderal (Grime et al. 1988, 2007).

Flowers are axillary, solitary in the upper part of the stem and are pollinated by small flies and bees, or else self-pollinated. In dull weather, the flowers open less widely, so that the anthers and stigma lie in contact, automatic pollination being effective (Hutchinson 1972; Garrard & Streeter 1983).

V. agrestis is distinguished from V. persica (Common Field-speedwell) by its smaller flower (only 4-8 mm in diameter) and the lobes of the fruit not diverging. It is separated from V. polita (Grey Field-speedwell) by the lower petal (at least) being milky-white and the corolla not being a uniform dark blue: it also has brighter green foliage, the lower leaves opposite, gradually becoming alternate upwards (Hutchinson 1972). The fruit capsule is clothed with numerous glandular hairs and normally contains from 8-16 seeds which are about 1.5 mm in their longest dimension, compared with 1.3 mm for V. polita. In both V. agrestis and V. polita the seeds are very remarkable, being boat-shaped with transverse ridges on the convex surface (Salisbury 1964; Garrard & Streeter 1983; Webb et al., 1996). Another description of the seed of V. agrestis says they are, "grub-like, with wrinkled beady margins and scooped out in the middle" (Hutchinson 1972).

Fermanagh occurrence

There are only two pre-1975 records for this weedy annual in Fermanagh and it was not until RHN began recognising it in 1990, that 15 subsequent sites were added by him. The two early records were Stewart's first listed above and a 1900 Florencecourt find by Praeger published by him in Irish Topographical Botany the following year. The flowers are parti-coloured (in shades of white, pale blue or pink), the lower petal or petals being either much paler blue or white. The Fermanagh Flora Database contains a total of 18 records from, as the tetrad map indicates, 16 widely scattered tetrads, 15 of them with RHN's records.

Irish occurrence

Previously, Green Field-speedwell was a widespread, if not a common weed of arable agriculture and cultivated ground, occurring in every Irish VC (Cen Cat Fl Ir 2). However, it declined to its present rarity during the last 50 or more years (FNEI 3; Flora of Co Dublin). The species status was regarded by the Cen Cat Fl Ir 2 as, "possibly introduced", which is why it is not considered by Reynolds in her Cat Alien Pl Ir. V. agrestis was so common in the late 19th and early 20th centuries in both NE Ireland and in Co Dublin, that the authors of the county Floras did not include details of its sites (FNEI 1; Colgan 1904).

British occurrence

There has been a steady, long-term, marked decline in V. agrestis populations to scarcity or near rarity in Britain also, a process that was noted even in the first BSBI Atlas (Perring & Walters 1962). It was previously common and widespread in suitably disturbed cultivated ground in lowland England, but more scattered and local in the north and west, as well as in Ireland.

It is odd that of all the annual weedy species of dry, well-drained, stony or disturbed, moderately acidic, cultivated ground, V. agrestis should have declined quite so much. The enormous decrease of V. agrestis populations may be linked to the rise of the closely allied V. polita, as an example of competitive replacement (Salisbury 1964), or there could be similar interactions involving other weedy speedwells of similar habitats and habit, eg V. arvensis (Wall Speedwell), V. persica (Common Field-speedwell) and V. hederifolia (Ivy-leaved Speedwell). Detailed study would be required to demonstrate the reality of this possibility.

An alternative explanation recognises that there are many other previously frequent weeds of arable ground which have also disappeared, or almost so, eg Agrostemma githago (Corncockle), Centaurea cyanus (Cornflower), Papaver dubium (Long-headed Poppy) (including P. dubium subsp. lecoqii (Yellow-juiced Poppy)) and Scandix pecten-veneris (Shepherd's-needle). All of these were previously found in Fermanagh and throughout the country and have been effectively eliminated either by modern seed-cleaning processes and changes in, or intensification of, agricultural operations involving the heavy use of herbicides and fertilisers (A. Horsfall, in: Preston et al. 2002; Crawley 2005).

Species revised status

V. agrestis, together with V. polita, Centaurea cyanus and Scandix pecten-veneris are among the list of 41 species whose status Webb (1985) suggested require reassessment and which might well turn out to be best regarded as introductions to B & I. The current author (RSF) is pleased to see that the editors of the New Atlas have agreed with Prof Webb and now recognise the plant as an ancient introduction to B & I, ie it is an archaeophyte (A. Horsfall, in: Preston et al. 2002).

European and world occurrence

The species has spread from C & S Europe and adjacent parts of N Africa and W Asia to reach N Europe and is now thinly scattered across numerous parts of Asia (including the Far East), N America and New Zealand (Hultén & Fries 1986, Map 1657).

Names

The Latin specific epithet 'agrestis' is derived from 'ager', meaning 'field', and translates as 'of fields', 'growing in the fields', or 'wild on arable land' (Gilbert-Carter 1964; Gledhill 1985; Stearn 1992).

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