Field Cow-wheat, Melampyrum arvense
Last week we went back to the Isle of Wight for a week (see my 2016 blog posts about Ribwort Plantain and Ivy Broomrape). We saw twenty species of butterflies, 29 species of bees and lots of other interesting invertebrates, Wall Lizards, a Red Squirrel and several new species of plants. The most spectacular and beautiful of these new plants was undoubtedly Field Cow-wheat, Melampyrum arvense.
Field Cow-wheat is now a rare plant in the British Isles, and is found in only four sites in South-east England. It is a member of the family Orobanchaceae, along with Ivy Broomrape and Purple Broomrape. It is a hemi-parasite: it possesses chlorophyll and makes its own sugars but it also takes some of its nutrients from its hosts, which include grasses and crops such as alfalfa.
Field Cow-wheat is an annual. It grows to 50cm tall and has upright stems with opposite pairs of lanceolate leaves, topped by flower spikes from May to September. Our plants were just beginning to flower on 23rd May. The flowers are mauve and yellow and grow from long, spiky mauve bracts. I can recommend the superb photographs and descriptions on the Wild Flower Finder and NatureGate websites. The Wild Flower Finder website describes the unopened flowers as “like a Guppie fish or some kind of whale with a trimeran or speed-boat type keel. Note too the walrus-type moustache.” The bracts have minute nectar-producing glands which attract ants, bumblebees and other insects. The flowers are pollinated by bumblebees.
Field Cow-wheat was first recorded in the British Isles in 1724, introduced accidentally as a contaminant of crop seeds. Elsewhere in Europe the plant is a more ancient introduction, classed as an archaeophyte, a plant introduced before 1500.
In the 19th and early 20th Century, Field Cow-wheat could be a major nuisance for farmers and on the Isle of Wight it acquired the local name of ‘Poverty Weed’. It was “so abundant as to render the bread discoloured and unwholesome, the seed being ground up with the wheat”. The plant’s scientific name is made up of arvense (Latin for ‘of cultivated land’) and Melampyrum, from the Greek words melas– (‘black’) and –pyros (‘wheat’). By the 1930s, improved preparation techniques resulted in cleaner flour and began the demise of the plant.
Field Cow-wheat seeds contain a iridoid glycoside, aucubin. Aucubin is slightly toxic and may make plants less attractive to herbivores; it is also found in (and named after) Aucuba japonica, the Spotted Laurel. Aucubin has antimicrobial and anti-inflammatory properties and appears to protect against liver damage and to speed healing of oral wounds.
Outside the British Isles, Field Cow-wheat is distributed throughout Western Europe, with the exceptions of central and southern Spain, southern Italy, Ireland, Iceland, Norway, central and northern Sweden, and northern Finland. It can also be found in parts of Turkey and the Ural Mountains.
Field Cow-wheat is in decline in Britain, France, Belgium, Germany, the Netherlands and Finland. In Britain, its decline is due to improved seed cleaning, agricultural intensification. The plant is also intolerant of both strong competition and heavy grazing. Fortunately, the site where we saw it is being well managed by the Hampshire and Isle of Wight Wildlife Trust and the plant is gradually spreading from a bank into the adjacent field.
“Like a Guppie fish or some kind of whale with a trimeran or speed-boat type keel. Note too the walrus-type moustache.” Field Cow-wheat, Melampyrum arvense, in close up.
