Purplish Pink parasite

June in England is wildflower time. Even very ordinary flowers are exquisite in closeup, like this clover:

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There is one particular field in Sherborne where every year I find this rather interesting orchid-like flower, the Common Broomrape, Orobanche minor. These were about 20cm tall, and the flowers are about 15mm long.

:

Common Broomrape

It is not an orchid, and it has no chlorophyll, so it can’t photosynthesize. Instead, it is a parasite on other plants, including both clover and vetch. The fine roots of the broomrape penetrate the larger roots of the host, reaching the vascular tissue. They usually severely hurt the host plant, and can be a major problem for farmers. In the USA, it is federally listed as a noxious weed, and banned.

The whole broomrape plant is covered in globular hairs,

Common Broomrape

The hairs are thought to serve the purpose of discouraging ants and other non-flying (and thus non-pollinating) insects from stealing the nectar. In these two photos you can see insects that have become entangled in the hairs: here’s one

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and this one:

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The burgundy stigma has two bulbous ends, and curves downwards, so an entering insect (usually a bee)  can’t avoid brushing its back up against it, and transferring pollen.

Common Broomrape

Once pollinated, they produce huge numbers of tiny seeds, which are disseminated by the wind, and washed down into the soil when it rains. If they make contact with the root of a potential host plant they germinate, insert their tiny root into the host, and the whole cycle restarts.

PS: The name ‘broomrape’ comes from the broom plant, a common host for broomrape, and the Latin word ‘rapum’, which means root or tuber.  

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