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Sherardia arvensis L., Field Madder

Account Summary

Presumed native, very rare and local, sometimes a casual or naturalised weed. European southern-temperate, but widely naturalised in both hemispheres.

1884; Barrington, R.M.; Crom Castle Estate.

June to September.

Growth form and preferred habitats

This distinctive, prostrate or sprawling, loose, multi-stemmed and very much branched from the base, mat- or tuft-forming, annual, 4-22 cm long, the branches quadrangular, the angles bristly with stiff, short prickles (pricklets). Leaves 4-8, but usually six in a whorl, sessile, lanceolate, entire, acute, leaf blade 5-18 × 1-5 mm, ± glabrous, but furnished with forwardly directed short prickles, especially on the nerves below and on the margins. The current author believes the 'six leaves' in a whorl are actually two leaves, each with two leaf-like stipules. But what then of the four- and eight-leaved whorls?

S. arvensis is distinguished from Asperula spp. (Woodruff) by the calyx lobes. In Sherardia the calyx is 0.5-1.5 mm at first, enlarging slightly when in fruit. It usually has six erect, subulate lobes with short, rough, bristly hairs. The lobes are sometimes absent. In Asperula, the calyx is absent or vestigial and minute, represented by an indistinct annular ridge (Sell & Murrell 2006).

Previously, the bristly hairy nutlets of S. arvensis were a common contaminant of clover seed (which has always been sown in very large amounts) and in other agricultural crop seeds, and the species was much more frequent and widespread in arable fields than is the case today (Salisbury 1964, p. 129). It has been almost eradicated from agriculture by seed cleaning and the widespread use of herbicides, although it remains present on dry, sandy soil in pasture gaps, margins of arable fields, wayside banks, screes, disturbed waste ground, thin grassland and in lawns, where it flowers and fruits in a very dwarf form (Sell & Murrell 2006). It prefers dry, well-drained acid or calcareous soils and occurs to an altitude of 365 m. In terms of soil preferences, Field Madder appears to be more frequent where there is a somewhat higher lime content (as is witnessed locally in Fermanagh by its presence on the top of Knockninny Hill). The established strategy of S. arvensis is categorised as R/SR, meaning intermediate between a straight Ruderal and a Stress-tolerant Ruderal (Grime et al. 1988, 2007).

This ruderal annual is capable of persistence for 50 or more years in suitably disturbed open, dry ground.

Flowering reproduction

S. arvensis is distinguished from other members of the Rubiaceae family by its heads of small, pale to deep mauvish-pink, 4-petalled, narrowly tubular flowers, 2.5-3.0 mm in diameter, 4-8 in terminal and lateral clusters, each head surrounded by an involucre of up to ten connate (fused), leaf-like bracts, longer than the flowers (Butcher 1961; Garrard & Streeter 1983; Sell & Murrell 2006).

It flowers from May to November and is pollinated by flies and bees. The flowers are gynodioecious with an inferior ovary, the bisexual flowers being somewhat larger than the females (Hutchinson 1972). In the bisexual flowers, the stigmas are often receptive at the same time as the anthers that open at the same level, thus readily enabling self-pollination to take place. Nectar is secreted by a fleshy disk surrounding the base of the style on the top of the ovary.

The fruit capsule, 3.0 × 3.5 mm (or 4.0 × 1.6 mm according to Salisbury 1964), is ovoid, covered with bristly hairs and crowned by 4-6 persistent calyx teeth. The fruit consists of two single-seeded portions (nutlets or mericarps), each enclosed in half the calyx and crowned on top with two or three of the spiny sepal teeth (nutlet measuring 2-3 mm, according to Sell & Murrell 2006). The convex surface of the fruit nutlet is covered with short appressed bristles, which readily allows the propagule to attach to the fur of small mammals or to clothing, thus aiding dispersal (Butcher 1961; Salisbury 1964, p. 183; Hutchinson 1972; Clapham et al. 1987). The seed within the nutlet is 0.1-0.2 mm, oblong, grooved and minutely reticulate (Sell & Murrell 2006). As noted above, the seed is persistent in the soil seed bank, a proportion surviving for up to five years (Thompson et al. 1997) and possibly a very small proportion for a lot longer (Grime et al. 1988, 2007).

Fermanagh occurrence

It is odd that S. arvensis has been recorded from every Irish VC (Cen Cat Fl Ir 2) and yet should be so very rarely listed in Fermanagh. It has been found in just four tetrads in the SE of the VC, three of which have post-1975 records. Apart from the first Fermanagh record listed above, the remaining station details are: Knockninny summit, 1948, MCM & D; refound by I. Rippey, 1984 and RHN in 1988 & 1990; Knockmackegan railway level-crossing, 1951, MCM & D (railway long gone and plant not refound); Inisherk Island, Crom Castle Estate, 21 August 1986, A.S. Mullin, P. Corbett & J.C.L. Phillips; refound here on a boating slipway, 1989, RHN.

British and Irish occurrence

S. arvensis occurs widely across most of B & I, but in its present distribution it becomes progressively rarer and more coastal as one goes north of Cumberland (VC 70) and Midlothian (VC 83) in Britain, and likewise the same coastal trends occurs in Ireland north of Cos Sligo (H28) and Down (H38). An Irish Flora (1996) describes the species as occasional, whereas earlier editions gave it as frequent. A further suggestion of species decline appears in the FNEI 3, where it was said to be, "somewhat unpredictable in its appearances at sites; often not persistent or occurring in temporary habitats". In the Urban Flora of Belfast, Beesley & Wilde found S. arvensis in just two locations and described it as rare.

This previously more frequent weed of arable agriculture appears to have become a casual or rare colonist of sites subject to summer drought, on open rocky turf and in marginal or linear habitats in most areas of B & I (Graham 1988; Swan 1993; Woods 1993; Brewis et al. 1996).

Fossil history and species status

S. arvensis was first reported in Britain in 1953 as fossil seed from a deposit dating from the Late Bronze Age. This was apparently the earliest European record of the plant, which had a history of cultivation and use as a dye plant by the ancient Greeks and Romans (Godwin 1975). In the 17th century, Field Madder was a frequent agricultural weed, whilst its roots could be used as an inferior source of the red dye, madder. It has been suggested that Field Madder may only be native in some western coastal habitats in Britain, and may well be an archaeophyte introduction elsewhere (see W.R. Meek, in: Preston et al. 2002).

This proposal had previously been discussed nearly 40 years earlier by Salisbury (1964, p. 29). He pointed out that Field Madder and many other familiar arable weed species first appeared in Britain in the Neolithic Age, and that it and they very probably and readily could have been introduced as a contaminant of clover seed or other imported crop seeds. Furthermore, Salisbury considered it very likely they were subsequently reintroduced, over and over again to B & I in this manner, until they became limited, or almost completely eliminated, by modern scientific methods of seed cleaning and the widespread use of herbicides.

The BSBI Local Change Survey (1987-2004), found a marked resurgence of S. arvensis in sampled hectads in S England, however, which may reflect warmer, drier summers associated with recent rapid climate change that probably suits the growth of a species introduced from the Mediterranean region (Braithwaite et al. 2006).

European and world occurrence

S. arvensis is a member of the European Southern-temperate phytogeographical element and is considered a native of Mediterranean and SE Asian grasslands. It has been a common crop seed contaminant and arable weed until recent times and has been introduced with crop seed and distributed throughout most of Europe to 67oN in Norway. It remains well represented throughout the Mediterranean basin including the islands and Macaronesia. It is also present in Iceland and extends into W & C Asia including the Caucasus, Turkey, Saudi Arabia to Kazakhstan and Siberia and southwards to N Africa. It is widely introduced and naturalised in N America, especially the Pacific States, plus in Ethiopia, Sudan, S Africa, S Australia, New Zealand and in other temperate countries such as Taiwan, Mexico and C & S America (Hultén & Fries 1986, Map 1513; Clapham et al. 1987).

Names and uses

Field Madder is the only species that belongs to the genus Sherardia, ie it is monotypic, and was named in honour of Leicestershire-born William Sherard (1659-1728). Sherard, who endowed the Sherardian Professor of Botany in the University of Oxford, was an architect of 18th-century botany. He identified and nurtured botanical talent, maintained intellectual networks and built one of the world's largest pre-Linnaean herbaria.

Its roots provided a dye, but it was a very poor pink substitute for 'proper' Red Madder, Rubia tinctorium, 'Rose Madder', 'Common Madder' or 'Dyer's Madder', a reliable vivid red dye used worldwide for thousands of years, and going back to Biblical, Ancient Greek and Roman times (Chenciner 2000). Interestingly, Chenciner lists a long catalogue of plants related to R. tinctorium reportedly used as substitute dye plants around the world, but there is no mention whatsoever of Sherardia arvensis.

Threats

None.