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Spergula arvensis L., Corn Spurrey

Account Summary

Introduction, archaeophyte, occasional, but locally abundant. Eurosiberian wide-temperate, but widely naturalised and now both circumpolar and well represented in the southern hemisphere.

1881; Stewart, S.A.; Co Fermanagh.

June to December.

Growth form and preferred habitats

A mainly summer annual, S. arvensis is an ascending or erect, glandular-hairy, somewhat sticky plant, often unbranched, or with 1-8 long branches arising from near the base. Stems bear slender, linear, fleshy leaves that are opposite but often appear whorled due to the presence of leaf clusters or fascicles in the stem leaf axils. Previously a common arable weed of as many as 25 different crops, and particularly associated with cereals and flax, S. arvensis is now a declining ruderal species of fertile, disturbed habitats, including sand and gravel quarries and more or less sandy, moist lake foreshores (Holm et al. 1977; Grime et al. 1988; Rich & Woodruff 1996). S. arvensis appears to prefer light, sandy, acidic, moderately fertile, lowland soils (pH 4.6-5.5), and it shows a slight (or sometimes more definite) calcifuge tendency.

Although S. arvensis is said to be intolerant of trampling (New 1961), one of the most predictable habitats we find it in is around field gateways where the soil is poached and manured by concentrations of cattle. S. arvensis never occurs as a member of a stable, closed vegetation community. Rather, it is confined to open or disturbed situations where bare ground is available for colonisation. It is frequently found in abundance in recently sown fields or garden lawns, but plants quickly disappear after the first year as the closed turf gradually develops. Another situation where S. arvensis can become conspicuously abundant is on the exposed shores of lakes after a period of hot, dry, summer weather.

Flowering reproduction

S. arvensis reproduction and survival relies entirely on seed. The plant grows rapidly, flowers within eight weeks of germination and seeds a fortnight later (New 1961). On account of its rapid growth and reproductive cycle, two generations readily fit within a growing season. The tiny white or slightly pinkish flowers are 97% selfed, although a range of insect visitors including flies and bees have been recorded (Knuth 1906-9). Sometimes flowers are pollinated and fertilised in bud (ie cleistogamy occurs) (New 1961). Flowers do not open until about mid-day, and they close again in the late afternoon. In cool or dull conditions, they remain shut. Depending upon source, an unpleasant odour is emitted by the open flowers (New 1961), or they are slightly fragrant (Jonsell et al. 2001)!

Fruit capsules are ovoid and up to twice the length of the sepals. They split to form five broad teeth and release the seed. Seeds are lenticular, rugose, with or without club-shaped papillae, narrowly winged and black, brownish, or grey in colour. The number of seeds produced per plant is between 300-7,500, depending upon the number of capsules produced. This in turn reflects plant size and the degree of branching. During experimental studies in India using local seed, Trivedi & Tripathi (1982) found seed production varied from 540-3,155 per plant, highlighting the great degree of plasticity found in this cosmopolitan species.

Fossil record and status

S. arvensis is a cosmopolitan species of unknown origin which Holm et al. (1977) recognised as one of the world's worst weeds, particularly of cereals. Until very recently, S. arvensis was generally assumed to be native in Britain & Ireland (eg Stace 1997). However, Godwin (1975) pointed out that fossil finds are almost exclusively from archaeological sites from the Neolithic onwards, so early introduction could not be ruled out. The editors of the New Atlas have now recognised it as an ancient introduction (Preston et al. 2002).

Variation

S. arvensis is very variable with respect to habit, stamen number and even seed surface texture. Some of this variation is environmentally induced, including the degree of branching (and hence flower and seed production), degree of glandular hairiness and presence or absence of papillae on the seed coat (New 1961). A cline in the frequency of the two seed forms (papillate and non-papillate) exists across Britain & Ireland, running in a north to north-west direction. The papillate form (var. arvensis) is predominant in the south, but as one goes north and westwards it is gradually replaced by the smooth form (var. sativa). A matching cline with respect to hairiness exists, the densely hairy form being predominant in the north and west of Britain & Ireland. These genotypic differences relate to general climatic factors: smooth seeds germinate better than papillate at lower temperatures, but they proved more sensitive in this respect to higher moisture tensions (ie drier conditions) than the papillate ones (New & Herriot 1981).

Germination

S. arvensis germinates in the spring (usually in April) from a very large, persistent seed bank. It cannot easily be classified as a summer or winter annual, since although its seeds germinate in spring and summer, which is characteristic of a summer annual, dormancy seems to be broken by high temperatures, which is typical of winter annuals (Karssen et al. 1988). Corn Spurrey appears to display a dormancy cycle varying seasonally from conditional dormancy to non-dormancy (Milberg & Andersson 1998). Bouwmeester & Karssen (1993) found that dormancy was broken in spring and re-induced in autumn with rising and falling temperatures respectively. They also showed, however, that exposure to light, addition of nitrate and a desiccation treatment of seeds prior to the germination test strongly stimulated germination. Furthermore, a combination of these factors allowed S. arvensis to germinate in all seasons. Milberg & Andersson (1998) found that seed buried outdoors at the end of November and exhumed monthly for testing, germinated from March to December under two light treatments, but was greatest in the autumn months.

Seed dispersal

Seed transport is achieved through fruit capsules ingested and voided by grazing animals, such as cattle, sheep and birds (Holm et al. 1977). Seed is also unintentionally transferred in mud on farm vehicles and boots. Long-distance seed dispersal is again accidental, chiefly as a contaminant of agricultural seed (New 1961).

Seed longevity

In arable fields, S. arvensis can develop a huge, long-lived, soil seed bank of up to 23 million seeds per hectare (New 1961). Seed longevity is variously reported, maxima ranging from around 50 years (Chippendale & Milton 1934), or "at least 50 years" (New 1961), to less than 1% viability after 9.7 years (Conn & Deck 1995). There is also a fascinating report of ancient seed of S. arvensis recovered from archaeologically dated soil samples proving viable after burial for 1,700 years (Odum 1965).

Fermanagh occurrence

S. arvensis is still a widespread species in N Ireland, but Fermanagh is the one area where there are gaps in the hectad map. Locally, it has been recorded in 52 tetrads, 9.9% of those in the VC. It is occasional and as the distribution map shows, it is thinly scattered across the county, being most frequently found in the better farmland east of Lough Erne. Corn Spurrey appears particularly frequent around the Tempo area, E of Enniskillen, although with the exception of around exposed lakeshores, even here it is rarely abundant. It should also be looked out for on piles of topsoil and around recently disturbed roadsides, or in newly sown grasslands.

British and Irish occurrence

Common and widespread on suitable soils throughout. It mainly avoids basic calcareous and waterlogged sites. S. arvensis has declined markedly due to industrial seed cleaning and the widespread use of herbicides (New Atlas). It really has become more of an occasional species, often found only in small numbers.

European and world occurrence

Area of origin unknown, but the species common in C & E Europe, thinning eastwards in the Mediterranean basin. S. arvensis becomes much more rare in eastern Europe. Jalas & Suominen (1983, Map 990) show it stretching from the far north of Scandinavia (70°N) to the south of Spain, but becoming rare in Greece and Crete. It is introduced almost worldwide, including commonly in N America, especially in eastern states (Hultén & Fries 1986, Map 770). It is almost cosmopolitan, from the arctic to the tropics, although confined to high ground in the latter (New 1961).

Nutrition and Uses

Despite its small size and very narrow leaves, the species is very nutritious and is avidly eaten by farm and other animals, being rich in phosphate, magnesium and sodium (Wilman & Riley 1993). In the past, it has also been cultivated and eaten as food for humans, not only in times of famine. It was part of the last meal of Tollund Man (one of the archaeological bog bodies). Corn Spurrey was eaten by humans in Shetland in historic times, being ground into meal and used for bread (Grigson 1987).

As grasses can be deficient in some elements for animal production purposes (including N, P, Mg, Na and sometimes, Ca), comparative digestibility trials using sheep were carried out by Derrick et al. (1993) who found that the voluntary intake of S. arvensis measured in terms of weight was 22% higher than that of Perennial Rye-grass (Lolium perenne). Fream (1900) reported S. arvensis being sown for grazing and silage in the past. The live-weight gain of lambs fed on Corn Spurrey has been found to be higher than that on a Rye-grass diet, and a combination of palatability, a lower proportion of cell wal and ease of physical breakdown were the significant digestibility features compared with grass (Derrick et al. 1993). On the other hand, the lower concentration of water-soluble carbohydrate in Corn Spurrey and five other dicotyledonous species compared with Rye-grass, would put them at a disadvantage from the point of view of silage making (Wilman & Derrick 1994). The overall conclusion of these experimental measurements was that Corn Spurrey and other common dicotyledonous grassland weed species such as Common Chickweed (Stellaria media), Broad-leaved Dock (Rumex obtusifolius), Ribwort Plantain (Plantago lanceolata) and Dandelion (Taraxacum officinale), extend the range of concentration of some major elements in herbage beyond that normally found in temperate grassland.

There is little evidence of medicinal use of the herb, although Allen & Hatfield (2004) quote John Parkinson (1640) who claimed that country folk used the sap of the bruised plant for healing cuts.

Names

First recorded in Great Britain by l'Obel (De l'Obel & Pena 1571), Grigson (1974) follows Lyte (1578) in suggesting the name 'Spurrey' or 'Spurrie' comes from the Dutch 'spurie' (West Frisian, 'sparje'), from which l'Obel (himself Flemish), seems to have coined the Latinised name 'Spergula'. However, there are alternative explanations of its origin. One interesting suggestion is that spurrey derives from the arrangement of the leaves, "On the stalk are set ... small narrow leaves, waving or bending in manner of a star or spur rowel of many points" (Britten & Holland 1886). Prior (1870) believed it more likely that Spurrey came from Spergula, and suggested that the latter was a contraction of 'Asparagula', a presumed diminutive of 'Asparagus', "a plant which the Spurrey somewhat resembles".

In England, an alternative name for Spurrey was 'Francke' (Lyte 1578), 'Franke Spurrey' (Gerarde 1633), 'Franck Spurry' or 'Francking Spurnewort' (Parkinson 1629), meaning a fattening herb for cattle. The name 'Francke' given by Lyte, is said to be derived from an obsolete word for a fattening pen or sty (Prior 1870; Britten & Holland 1886; Grigson 1974).

In addition to the above, Grigson (1987) lists a total of 17 further local common names for the plant, some of which are regularly applied to alternative species (eg Dodder (Cuscuta spp.)), or which denote a vaguely similar appearance (eg Toadflax, referring to Linum catharticum, Fairy -, Mountain - or Purging Flax).

Threats

None.