Lichen.

I'm not good on lichens so I can't tell you what these are but there are several distinct species here. When we first moved to Roslin in 1979 there were a few crustose specimens (those varieties are the most tolerant of pollution) now these foliose ones are in abundance. Since the mid to late 80s we have seen coal fires disappear along with leaded petrol, and cars now have catalytic converters; all of these have benefited the lichen population down in the Glen.

When I was at school, we were taught that lichens were unique in that they were symbiotic organisms, that is organisms made up of more than one species - in this case a fungus and an alga; now we know that most, if not all organisms are symbiotic having complex relationships with a vast number of different species, such is progress.

It struck me, as a young adult, that my grandfather was a young adult when the Wright Brothers made the first flight in a heavier than air machine and when Marconi made the first significant communication by radio, later, he also watched the first moon landing on television. Before he was born, technological progress was very slow by comparison and before his grandfather was born it was virtually static.

I came across a more impressive example of progress about ten years ago when I did a post-grad course, something of an achievement as I am not a graduate; the prof had taught electronics to young men in Papua New Guinea, they had been born into a stone-age society and their tribe (the Fore people) had recently suffered an epidemic of kuru, a spongiform encephalopathy (as is mad cow disease) transmitted by cannibalism practised as a funeral ritual. A high price to pay for honouring your dead.