Pros and cons

At last: the sun shone, birds sang, bees buzzed, flowers bloomed. It was the perfect day for a long walk.

This was the apogee of my walk where I turn for home. A glade of rhododendron bushes in a secluded valley: they must have been planted years ago. Up above two planes inscribe their aerial scribble upon the cerulean.

I am ambivalent about both rhododendrons and contrails. The first make an exotic splash of colour in the British landscape, and the way the flowers unfurl from the buds like parachute silk involves a miracle of packaging. But the Victorians who planted it in their gardens and estates did a great disservice to the countryside because it has caused severe damage. Powerfully invasive, it spreads rapidly, destroying habitat for native species with its densely shaded ground cover. It contains grayanotoxins which make it inedible and although bees love it, honey made from the nectar can cause "mad honey disease" which produces unpleasant though non-fatal symptoms (and incidentally was used for biological warfare by the Romans.)

Contrails, the exhaust vapours emitted by jet engines, can look attractive criss-crossing the sky and they always remind me of the excitement of long-haul flights. But there's little doubt they are harmful to the environment. "Some days they fade away within a few minutes and they pose no threat. It is the days that perfect conditions exist when they do their damage, drifting and expanding to several thousand square miles and blanketing the lowest atmosphere of Earth through the night, unnaturally trapping heat." That's quite apart from the amount of fuel that the planes consume.

On the plus side, I found a field of cowlips and discovered an unusual fungus which I have identified (I think) as Macrotyphula fistulosa.