Start the week with a wildflower no 54. Knapweed broomrape, Orobanche elatior; Greater Knapweed, Centaurea scabiosa

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Broomrapes survive by thieving.  Their seeds remain dormant until compounds produced by their favoured host plant stimulate germination. It totally lacks the ability to photosynthesise, but once attached to the host plant roots it robs it 
of water and nutrients. Sneaky!

There are numerous broomrape species, often named after the plant they parasitise, eg ivy broomrape. Common broomrape is less fussy, using several plants, although with a preference for clovers and vetches.  Knapweed broomrape is much taller than Common broomrape  and in contrast is very particular. Only Greater Knapweed, (not the more widely distributed Common Knapweed, centaurea nigra) will do.   Knapweed Broomrape is nationally scarce but Wiltshire is one of its hot spots as chalk/limestone is what Greater Knapweed needs to thrive. 


Look for the broomrape and its host on the small lane linking the C151 with the Euridge Manor crossroad.  The easiest way to distinguish the knapweed species is to look at the leaves which are simple in Common, and multi-lobed in Greater Knapweed. The  flowerhead is larger, with an attractive outer fringe of florets. 


The species name scabiosa relates to its past reputation as a treatment for scabies.   Both knapweeds have a long history of use in wound healing (the Centaurea genus was named for the half-man half-horse centaur Chiron, who is said to have healed a wound on his hoof with knapweed.


Knapweed plants are rich in nectar and a magnet for bees and butterflies, especially the lovely marbled white.