top of page


Melampyrum arvense

Melampyrum arvense - Field Cow-wheat.JPG

A hemi-parasitic member of the Figwort family, occuring in open tussocky grasslands in field boundaries. It used to grow in abundance in crops, and was known as a 'poverty weed' due to its seeds reducing the market value of corn. It has now completely vanished from arable habitats and survives in a handful of sites where open soil conditions are managed for.

  • Rarity: 4 sites, in the south of England.

  • Cause of decline: Agricultural intensification.

Field Cow-wheat was once a relatively common sight in arable fields in the south of England, and on the Isle of Wight was reported as ‘over-running’ fields of wheat and barley. The name of the genus comes from the Greek words melas, meaning black, and pyros meaning wheat.


This is a reference to when seeds were harvested with wheat and after milling turned entire batches of flour a blue-black colour whilst also making it distasteful. In the early 19th century plants used to be pulled by hand and taken off to be burnt.

Originally believed to be parasitic directly on crops, recent research has suggested that the plants were in fact parasitic on the dicotyledonous plants growing among crops, which partially explains the disappearance of Cow-wheat amongst modern monoculture crops.


Its recent dramatic decline is undoubtedly linked to improvements in seed cleaning technology, which have prevented the seeds contaminating arable crops, coupled with an increased use of pesticides and a move towards spring sown crops.

Field Cow-wheat status report 2016

This report describes Field Cow-wheat at its only Hampshire site at Portsdown, set against its national conservation status

The species appears to favour dry chalky soils, and requires open conditions. However its parasitic nature means that full habitat clearance cannot be carried out, and a range of suitable host plants have to be retained alongside the Cowwheat.

Of the current four sites in the UK only one, St Lawrence Bank on the Isle of Wight, is considered as a true native site. Both the Brogborough and Portsdown sites are a result of successful translocations, although the former now only contains a handful of plants.

bottom of page