The Euphorbias, alias the spurges, include some of the most statuesque of garden plants. And in the natural woodlands the wood spurge commonly strikes a dramatic pose. Its large clusters of yellowish flowers formed not of petals but yellowish bracts are eye catching. Each plant stands up to eighty centimetres high. Each red stem has a perennial drapery of drooping large thick, deep-green leaves which tend to be purple on the underside. The young shoots with their small, still growing leaves usually flop to one side. A thick white latex oozes out from any broken stem. This latex is extremely acrid in taste and can burn the skin. It is hardly surprising that one does not usually see any damage caused by predators. The plant is common throughout France, but in Britain it becomes rare north of a line from the Mersey to the Wash.

Here and there in the spring of 2007 I have seen stands of the plants with the topmost drooping growth replaced with clumps of broader pale yellow/green leaves standing straight. The photo compares the abnormal on the left (plus one fly) with the usual form on the right. My first thought was that the yellow form was just an aberration, a variation, but then I realised that groups of flies were settling on them. I also saw a small yellow slug eating a yellow leaf. Unfortunately when I brought the camera close enough to get a picture the flies tended to fly off. I picked a deformed stem and immediately smelt a powerful and delightful scent. In contrast the ordinary dull green and purple leaves smelt musty and earthy. The odeur of the deformed leaves reminded me of gardenias. It was so unexpected. One must suppose that the flies and slug were attracted to the smell and were devouring the exudations from the leaves which produced it. But what caused the smell? I remembered the experience from long ago of a similarly strong scent emanating from a fungus disease ( a 'rust' disease) on creeping thistle. Indeed, examination of the leaves under the microscope showed that each yellow leaf bore hundreds of minute red fungal pustules. These each exuded an aromatic liquid. Further research showed it is a 'rust' Endophyllum euphorbiae-sylvaticae, rarely found in Britain. It only lives on the wood spurge and no other species of spurge. It has contrived to change the shoots of the spurge into yellow scented 'flower' forms to attract the flies which would most surely carry the spores of the fungus to new plants. I also wonder if any other animals would eat these soft, yellow, scented leaves?

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