Hemi-Parasitic Plants

COMMON COW-WHEAT

Melampyrum pratense

Broomrape Family [Orobanchaceae]  
Formerly in: Figwort & Foxglove Family [Scrophulariaceae]

month8May month8jun month8june month8jul month8july month8Aug month8sep month8sept

status
statusZnative
 
flower
flower8yellow
 
morph
morph8zygo
 
petals
petalsZ1
 
type
typeZtrumpet
 
stem
stem8square
 
rarity
rarityZscarce
(ssp. commutatum)

ssp. Pratense

(the much more common sub-species)

5th June 2014, Sandstone Trail, south of Frodsham Photo: © RWD
A wide spread of the low flowers.


6th July 2007, Colwith Force, Little Langdale. Photo: © RWD
The leaves are similar to those of grass, but much shorter and slightly paler.


6th July 2007, Colwith Force, Little Langdale, Cumbria Photo: © RWD
The grass-like leaves are well camouflaged by the grass.


1st Aug 2007, Darwen Moor, Darwen, Lancs. Photo: © RWD
The leaves are long-lanceolate.


1st July 2005, Eskdale Valley. Photo: © RWD
The leaves vary in length, longest near the root end of the plant, but are long-lanceolate in shape.


6th July 2007, Colwith Force, Little Langdale, Cumbria. Photo: © RWD
the flowers are in adjacent pairs just above the oppositely paired leaves - all on a square stem.


6th July 2007, Colwith Force, Little Langdale, Cumbria. Photo: © RWD
The flowers always grow in adjacent pairs, much like does Skullcap.


6th July 2007, Colwith Force, Little Langdale, Cumbria. Photo: © RWD
The leaves are on short stalks. The stem square. Despite the leaves coming off the square stem on alternate siudes of the stem, the flowers seem to contrive to all point in much the same direction. They apparently achieve this by the 90° twists between each pair of flowers on the square stem.


6th July 2007, Colwith Force, Little Langdale, Cumbria. Photo: © RWD
The 5 sepal teeth are surprisingly long and narrow. The upper lip (which when not yet opened) is narrow and the overall shape of the flower then is similar to another hemi-parasitic plant, Yellow-Rattle. When opened the upper lip has a short moustache and hairs from the lips.


1st June 2018, Seathwaite, Borrowdale Valley, Cumbria. Photo: © RWD
From beneath the flower the shape of the lower lip is concave a bit like that of a cobra about to strike. Both top and bottom lips are a bit thick-lipped.


1st June 2018, Seathwaite, Borrowdale Valley, Cumbria. Photo: © RWD
The lower lip looks thick because it curls over outwards and backwards.


1st July 2016, Limb Valley, Sheffield, South Yorks. Photo: © RWD
These specimens from the Limb Valley are definitely in the North of England (not South) and also growing in acidic moorland conditions amongst Bilberry and yet, contraditorily, some are pale yellow. And yet others are white or pinky-purplish. Perhaps the pale yellow colour (rather than deep yellow) is due to lack of sunlight - these specimens are similar to those of Small Cow-wheat (which also do not have lower-petal teeth which are reflexed, but rather like this with 2 or 3 teeth sticking out. However, this theory seems to be scuppered by the fact that no Small Cow-wheat has been recorded onto BSBI maps that is south of Dundee in Scotland in the last 2 decades! And the furthest south they ever got was Middleton in Teesdale before 1986 (where it has not been seen there since). So the conclusion is that these from the Limb Valley near Sheffield are of Common Cow-wheat, albeit with teeth not yet reflexed beneath...


1st July 2016, Limb Valley, Sheffield, South Yorks. Photo: © RWD
On the centrally placed pale yellow flowers, the lower lip has not yet curled around underneath and it is easily seen that they have three teeth; and inside two bumps (on the underside they are indentations). The topmost flower has a closed mouth and looks like a Bottle-nose Dolphin. Your Author does not know why the lower pair have purplish flowers apart from observing that they are decaying and it may be that the yellow dyes change to purple in the decay process - note that the sepal cup and teeth are already a deep brown-purple.




ssp. Commutatum

[RR]

28th June 2019, Garston Wood, Hampshire Photo: © Jill Stevens
The flowers of this alkaline-soil loving and much rarer ssp. commutatum are much pallor in colour than the normal acid-soil loving ssp. pratense


28th June 2019, Garston Wood, Hampshire Photo: © Jill Stevens
And the broadest leaves are about twice as broad as those of ssp. pratense


28th June 2019, Garston Wood, Hampshire Photo: © Jill Stevens
The much broader leaves of ssp. commutatum [the leaf length difference is not nearly as pronounced as is the difference in breadth].

Slight resemblance to :Skullcap, but Common Cow-Wheat is yellow not blue. The flowers themselves have some semblance to other hemi-parasitic plants such as Yellow Rattle (Rhianthus minor), but that is shorter and the flowers all yellow.

The flowers of Common Cow-wheat are usually pale-yellow and not rich yellow as most (all?) of the above photos show. This is because Common Cow-wheat occurs as either of two sub-species:

  • Common Cow-wheat (Melampyrum pratense ssp. pratense) which are rich-yellow and grow on acidic soils in the North (but also some in the South). The leaves below the bracts are 7 to 15 times longer than wide [length 2-8cm (max 1 to 11 cm) long and 2-10mm (max 1-20mm) wide]. It is by far the most common of the two. The above photos are of this sub-species, unless otherwise labelled.
  • Common Cow-wheat (Melampyrum pratense ssp. commutatum) which are pale-yellow and grow on alkaline calcareous soils mainly in the South. The leaves below the bracts are mostly only 3-8 times longer than wide [length 4-7cm (max 3-10 cm) long and 8-20mm wide ) outliers 4-27mm wide]. This sub-species is a rare [RR].

This is a  Hemi-parasitic plant, meaning that it relies on obtaining some of its nutrients from the roots of nearby plants even though it has chlorophyll in its leaves and is able to photosynthesize.

The leaves are hard to see blending in well with the grass it grows so well amongst. The yellow flowers always grow in pairs up the stem. The first pair to emerge being at the top of the (square) stem.

The sepal teeth are very long and have brownish markings.

The seeds contain high concentrations of the toxic glycosidic compound Rhinanthin (aka Aucubin) to deter animals from consuming them. Presumably the same compound is also found in Rhinanthus species such as Yellow Rattle (Rhinanthus minor) which are also hemi-parasitic plants.


USE BY BUTTERFLIES
LAYS EGGS ON CATERPILLAR CHRYSALIS BUTTERFLY
Heath Frittilary



  Melampyrum pratense  ⇐ Global Aspect ⇒ Orobanchaceae  

Distribution
family8Broomrape family8Orobanchaceaeae
 BSBI maps
genus8Melampyrum
Melampyrum
(Cow-wheats)

COMMON COW-WHEAT

Melampyrum pratense

Broomrape Family [Orobanchaceae]  
Formerly in: Figwort & Foxglove Family [Scrophulariaceae]

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