"You don't get the kind of sun now that you used to get, " said one of them.

"You're right there. We had proper sun in the good old hours. It were all yellow. None of this red stuff."

"It were higher, too."

"It was. You're right."

"And nymphs and larvae showed you a bit of respect."

"They did. They did," said the other mayfly vehemently.

"I reckon, if mayflies these hours behaved a bit better, we'd still be having proper sun."

The younger mayflies listened politely.

"I remember, " said one of the oldest mayflies, "when all this was fields, as far as you could see."

The younger mayflies looked around.

"It's still fields," one of them ventured, after a polite interval.

"I remember when it was better fields," said the old mayfly sharply.

"Yeah, " said his colleague. "And there was a cow."

"That's right! You're right! I remember that cow! Stood right over there for, oh, forty, fifty minutes. It was brown, as I recall."

"You don't get cows like that these hours."

"You don't get cows at all."

"What's a cow?" said one of the hatchlings.

"See?" said the oldest mayfly triumphantly. "That's modern Ephemeroptera for you. " It paused. "What were we doing before we were talking about the sun?"

"Zigzagging aimlessly over the water," said one of the young flies. This was a fair bet in any case.

"No, before that."

"Er... you were telling us about the Great Trout."

"Ah. Yes. Right. The Trout. Well, you see, if you've been a good mayfly, zigzagging up and down properly -"

"- taking heed of your elders and betters -"

"- yes, and taking heed of your elders and betters, then eventually the Great Trout -"

Clop

Clop

"Yes?" said one of the younger mayflies.

There was no reply.

"The Great Trout what?" said another mayfly, nervously.

They looked down at a series of expanding concentric rings on the water.

"The holy sign!" said a mayfly. "I remember being told about that! A Great Circle in the water! Thus shall be the sign of the Great Trout!"

The oldest of the young mayflies watched the water thoughtfully. It was beginning to realise that, as the most senior fly present, it now had the privilege of hovering closest to the surface.

"They say, " said the mayfly at the top of the zigzagging crowd, "that when the Great Trout comes for you, you go to a land flowing with... flowing with..."

Mayflies don't eat. It was at a loss. "Flowing with water, " it finished lamely.

"I wonder, " said the oldest mayfly.

"It must be really good there, " said the youngest.

"Oh? Why?"

" ‘Cos no-one ever wants to come back."

Whereas the oldest things on the Discworld were the famous Counting Pines, which grow right on the permanent snowline of the high Ramtop Mountains.

The Counting Pine is one of the few known examples of borrowed evolution.

Most species do their own evolving, making it up as they go along, which is the way Nature intended. And this is all very natural and organic and in tune with mysterious cycles of the cosmos, which believes that there's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone.

This is probably fine from the species' point of view, but from the perspective of the actual individuals involved it can be a real pig, or at least a small pink root-eating reptile that might one day evolve into a real pig.

So the Counting Pines avoided all this by letting other vegetables do their evolving for them. A pine seed, coming to rest anywhere on the Disc, immediately picks up the most effective local genetic code via morphic resonance and grows into whatever best suits the soil and climate, usually doing much better at it than the native trees themselves, which it usually usurps.

What makes the Counting Pines particularly noteworthy, however, is the way they count.

Being dimly aware that human beings had learned to tell the age of a tree by counting the rings, the original Counting Pines decided that this was why humans cut trees down.

Overnight every Counting Pine readjusted its genetic code to produce, at about eye-level on its trunk, in pale letters, its precise age. Within a year they were felled almost into extinction by the ornamental house number plate industry, and only a very few survive in hard-to-reach areas.

The six Counting Pines in this clump were listening to the oldest, whose gnarled trunk declared it to be thirty-one thousand, seven hundred and thirty-four years old. The conversation took seventeen years, but has been speeded up.

"I remember when all this wasn't fields."

The pines stared out over a thousand miles of landscape. The sky flickered like a bad special effect from a time travel movie. Snow appeared, stayed for an instant, and melted.

"What was it, then?" said the nearest pine.

"Ice. If you can call it ice. We had proper glaciers in those days. Not like the ice you get now, here one season and gone the next. It hung around for ages."

"What happened to it, then?"

"It went."

"Went where?"

"Where things go. Everything's always rushing off."

"Wow. That was a sharp one."

"What was?"

"That winter just then."

"Call that a winter? When I was a sapling we had winters -"

Then the tree vanished.

After a shocked pause for a couple of years, one of the clump said: "He just went! Just like that! One day he was here, next he was gone!"

If the other trees had been humans, they would have shuffled their feet.

"It happens, lad," said one of them, carefully. "He's been taken to a Better Place, you can be sure of that. He was a good tree."

The young tree, which was a mere five thousand, one hundred and eleven years old, said: "What sort of Better Place?"

"We're not sure, " said one of the clump. It trembled uneasily in a week-long gale. "But we think it involves... sawdust."

Since the trees were unable even to sense any event that took place in less than a day, they never heard the sound of axes.

Windle Poons, oldest wizard in the entire faculty of Unseen University - home of magic, wizardry and big dinners - was also going to die.

He knew it, in a frail and shaky sort of way.

Of course, he mused, as he wheeled his wheel-chair over the flagstones towards his ground-floor study, in a general sort of way everyone knew they were going to die, even the common people. No-one knew where you were before you were born, but when you were born, it wasn't long before you found you'd arrived with your return ticket already punched.

But wizards really knew. Not if death involved violence or murder, of course, but if the cause of death was simply a case of running out of life then... well, you knew. You generally got the premonition in time to return your library books and make sure your best suit was clean and borrow quite large sums of money from your friends.

He was one hundred and thirty. It occurred to him that for most of his life he'd been an old man. Didn't seem fair, really.

And no-one had said anything. He'd mentioned it in the Uncommon Room last week, and no-one had taken the hint. And at lunch today they'd hardly spoken to him. Even his old so-called friends seemed to be avoiding him, and he wasn't even trying to borrow money.

It was like not having your birthday remembered, only worse.

He was going to die all alone, and no-one cared.

He bumped the door open with the wheel of the chair and fumbled on the table by the door for the tinder box.

That was another thing. Hardly anyone used tinder boxes these days. They bought the big smelly yellow matches the alchemists made. Windle disapproved. Fire was important. You shouldn't be able to switch it on just like that, it didn't show any respect. That was people these days, always rushing around and... fires. Yes, it had been a lot warmer in the old days, too.