Field cow-wheat  (Melampyrum arvense)

This colourful endangered plant has pale green, toothed and narrow leaves that grow on opposite sides of the stem. The flowers grow in a spike known as an inflorescence, and are generally purplish-pink in colour with a yellow throat and lip. Long, thin bracts also emerge from the flower spike; these can be green, deep pink or white in colour (3). A local name for this species is 'poverty weed' as the seeds gave a bad taste to flour and devalued the price of corn (4).

This species was first recorded in 1724 in Britain, and is probably native to the Isle of Wight, but may be introduced elsewhere (6). Never a particularly common species, field cow-wheat was known from the south and east of England. At present it occurs at just four sites, in Wiltshire, Bedfordshire and on the Isle of Wight (6). It has been deliberately planted at some sites (6). Elsewhere it occurs in Europe, extending to the Ural Mountains in the east, southern Sweden in the north and the northern Mediterranean in the south (1). In recent years it has declined in France, Belgium, Germany and the Netherlands (6).

Formerly an arable weed, field cow-wheat has more recently been recorded from open grassland on the edge of a chalk cliff, on track edges, in a flowerbed, and by an old brick-pit (6). It usually grows on calcareous soils in grasslands, and tends to be associated with places that have recently been disturbed (1).

This annual plant is hemi-parasitic (1), this means that its roots attach to those of other plants and it is able to obtain some nutrition from them. Plants grown in the absence of a host fail to thrive. A wide range of plants can be used as hosts (1), especially grasses (6). Field cow-wheat flowers from June to September, the flowers being pollinated by bumblebees (6). The heavy seeds are poor dispersers and can stay dormant in the soil for about two years (6). They have a small oil body at one end, which is attractive to ants, who may carry the seeds to their nests, eat the oil body then discard the seed (6). By doing so they aid in the dispersal of the plant. The seeds are unusual in that they germinate in the autumn, and the roots develop well before the shoots (which develop in the spring); presumably this is so that the seedlings can attach themselves to the roots of host plants quite quickly (6).

Agricultural improvements such as improved seed cleaning and the use of herbicides and fertilisers have resulted in loss of species from arable fields (1). Field cow-wheat cannot cope with heavy competition or over-grazing, and requires some disturbance to its habitats. If conservation management ceased at most sites natural succession would result in the loss of suitable habitat, as scrub would invade (1).

As mentioned above, conservation management maintains suitable conditions for this species at most of the remaining UK sites (1).

For more on this species see the book: New Atlas of the Flora of Britain and Ireland, by Preston, C. D., Pearman, D. A., Dines, T. D. (2002). Published by Oxford University Press, London.

Visit the website of the Botanical Society of the British Isles at:
http://www.bsbi.org.uk/

Information authenticated by Dr P. J. Wilson.