Common cow-wheat

I hadn't realised what an attractive little flower common cow-wheat Melampyrum pratense is until I took these pictures, .... especially ........

.... from this angle, with those frilly edges at the entrance to the tubular corolla.

These plants were flowering in woodland on the north bank of the river Tees at Barnard Castle earlier this week. Cow-wheat is partially parasitic in the roots of a variety of woodland plants, although it always seems to be most abundant when its growing on bilberry, as it was here.

All the spring flowers are just a distant memory and there are few species in bloom in woodland but common cow-wheat is an exception and is at its best right now. This bumblebee was taking full advantage, collecting pollen and nectar.

Vegetable Vampires 2: Lousewort

Lousewort Pedicularis sylvatica is one of several members of the foxglove family (Scrophulariaceae) that have evolved to become hemiparasites, attaching themselves to the roots of surrounding plants and siphoning off their water and dissolved mineral supply.  Lousewort leaves are convoluted and quite small in comparison with the flowers, which sit inside an inflated calyx that later encloses the seed capsule.

I've seen several suggestions concerning the origin of the name 'lousewort' but one plausible explanation is that it sometimes tends to grow in seasonally wet pastures where there's a high incidence of parasites that infest grazing animals. William Withering, the 18th. century physician and botanist, issued stern advice about the dangers of this plant to livestock. Writing in his Botanical Arrangement, published in 1776, he warned "If the healthiest flock of sheep are fed on it, they become scabby and scurfy in a short time; the wool gets loose, and they will be over-run with vermin". 

Marsh lousewort P. palustris, sometimes known as red rattle, grows in much wetter, permanently boggy sites. Common lousewort is a ground-hugging plant but marsh lousewort sometimes grows to 50cm. or more in height. William Withering also had a low opinion of this plant, commenting that "This is an unwelcome guest in meadows, being very disagreeable to cattle".

For more hemiparasites, click here

Vegetable Vampires 1: Common Cow-wheat

Backstone Bank wood near Wolsingham in Weardale has an interesting ground flora - one factor that qualifies it for SSSI status - and it includes this attractive little plant that blooms amongst the bilberry around the western edge of the wood. This is common cow-wheat Melampyrum pratense and although it looks harmless enough it's a partial parasite (hemiparasite) on the roots of bilberry. Its green leaves carry out photosynthesis and produce sugars but its roots invade those of the bilberry, siphoning off water and mineral nutrients.

Specialist hemiparasites like this thrive in soils with low fertility where there is intense competition for essential but scarce minerals, like nitrogen and phosphorus, because they are the botanical equivalent of vampires, tapping into the internal plumbing system of their host to supplement their own nutrition.

This is common cow-wheat but for pictures of its much rarer cousin small cow-wheat Melampyrum sylvaticum take a look at Mark's Beating the Bounds blog.

Some plants (holoparasites) have taken parasitism one step further, losing their chlorophyll and becoming totally dependent on their host for all their nutritional requirements - you can find a common example here and an extremely rare and beautiful example here.