And then the pairing-off had begun, and that had made things worse yet. With six men and four women, none of them partners before the landing, there was always going to be trouble. There seemed to be no gays in the party, which might have made the situation more complicated, or less, though the men joked bleakly about experimenting.

The pair-ups themselves kind of surprised Yuri. Of the men he’d never have tagged Lemmy as a winner, but pretty soon Pearl Hanks had made clear her preference to be with him. Everybody knew Pearl had once been a hooker, and some of the men, Onizuka, Harry Thorne, still looked at her that way. Maybe she had attached herself to Lemmy precisely because he didn’t react to her like that. And maybe she was calculating on Yuri protecting her, as she might think he protected Lemmy. It was all complicated, a game of human chess.

Martha Pearson, meanwhile, was sleeping with John Synge. That was less of a surprise, a businesswoman from Hawaii with a lawyer from New New York, they were similar types. But maybe that similarity was why they fought all the time they were together, if they weren’t asleep or screwing.

And Abbey, maybe the strongest woman of all, had surprised everybody by swooping down on Matt Speith, the artist with no art to make, maybe the most useless, skill-light, disoriented person in the camp. It was obvious who was in control in that relationship. Yuri speculated privately that Abbey had picked Matt as a kind of shield, to keep the other men off. But Mardina was more generous. Maybe she liked his nice soft artist’s hands, she said. Or maybe the ex-cop liked having somebody to protect.

Mardina herself didn’t pair off with anybody. She’d had approaches, more subtle or less, from the leftover men, Onizuka and Harry – not from Yuri. But she had no trouble brushing these guys off.

So that left Yuri, Onizuka and Harry without a woman. It drove Onizuka and Harry crazy very quickly, it seemed to Yuri. After all, this was all there was, the ten of them, no more choice of partners – not until their sons and daughters started growing up someday to widen the pool. There had been more choice even in the hulls: lose out now and you’d have lost out for life. Sometimes Onizuka and Harry would talk loudly about sharing partners, bed-hopping. It would be genetically efficient for the women to have babies with more than one partner; it was what Major Lex McGregor would have wanted, so they said. Nobody in a relationship listened.

Yuri didn’t care. It seemed to him the partnerships had formed up for mutual protection, maybe for comfort. Not for any logic concerning the destiny of the colony in years or decades or generations. And certainly for nothing you’d recognise as love. Right now he didn’t feel like he needed any of that, and nor, it seemed, did Mardina. But Onizuka and Harry glared and spat.

At least on this trek to the forest they would be able to get away from the camp, if only for a few hours. But as Onizuka snarled at Lemmy, and Lemmy cowered by Yuri’s side, Yuri saw that they hadn’t been able to leave their flaws and rivalries behind.

As they neared the edge of the forest they came to a bank of stromatolites. They kept calling these bacterial-colony formations by that name, inaccurate as it might seem to a biologist. These particular specimens were huge structures, much bigger than those near the Puddle – maybe four metres high, like tremendous tables with flat, flaring upper surfaces.

The ColU had taken samples from various stromatolites in the vicinity of the camp. They were all made of nothing but bugs, of course, layers of bugs and trapped dirt: Arduan bugs of course, like Earth bugs but not identical according to the ColU, in dense, complex layers, joined together in structures that might themselves be millennia old. But the uppermost layers contained photosynthesisers, bugs using the energy of Prox light to break down air and water to produce oxygen – a process similar to what had evolved on Earth, but a different chemistry under a different light. The ColU said it thought the stromatolites were actually this planet’s dominant primary oxygen producers. The ColU was always curious, always speculating; it was its job, it said once, to understand how this world worked, so it could be taken apart to become a human world, with the native life restricted to zones the humans didn’t need, maybe a few parks and botanical gardens. In Yuri’s day, as he recalled while the ColU described all this, they had had tree museums on Earth.

They didn’t linger long in the stromatolite garden.

Beyond, Yuri led the way into the deeper forest. The darkness gathered quickly, until they were surrounded by the strange trees of Per Ardua. The trunks rose slim and smooth and tall, without leaves or branches until they reached a canopy high in the air, where immense leaves like tipped plates blocked out the sky. The ground here was dry, compacted soil, covered by a shallow litter, mostly of tremendous leaf fragments like dead water lilies. There was no movement, no sound at first save the ragged breathing of the human party. But Yuri thought he heard a rustle, high in the canopy above.

Prox trees were different from Earth trees in most ways you could think of. True, your basic tree plan was the same, the roots, the trunk, the green leaves up top. But what the colonists called ‘wood’ self-evidently wasn’t wood at all; each trunk was more like an expanded version of the reed-like stems that grew in the Puddle. The saplings that grew at the southern fringe of the forest particularly provided decent timbers for construction, long and straight and sturdy, and with few branches save near the very top. But they’d learned that you couldn’t just throw a Prox log on the fire. You had to bleed it first, of a sticky, strong-smelling, purplish sap – ‘marrow’, they called it. The marrow itself was useful, however. Harry Thorne had experimented with fixing stone blades to poles with it. Harry had once been a farmer, even if the land he tended had been just a couple of acres in a high-rise, and for a man of densely urban twenty-second-century Earth he was good with his hands, Yuri thought.

A few hundred metres in they paused, shared water, took stock. Both Onizuka and Martha had crossbows to hand. The air was stained a deep green, deeper than any Earth green.

‘So,’ Onizuka said, ‘who knows anything about forests? Don’t ask me, I’m better at the oceans.’

‘Not me,’ Lemmy murmured. ‘And even in your time there were no forests left on Earth – right, Yuri? But I do know there’s a belt of this forest right around the face of Per Ardua, where there’s dry land anyhow. It’s the same all the way to the substellar point. You get these circular belts of similar kinds of landscape and vegetation and stuff, depending on the distance from the substellar point, the middle of the world’s face. Places that get the same amount of sunlight, see, get the same kind of growths. What you get is a planet like an archery target. Out here, near the terminator – trees.’

Onizuka grinned. ‘An archery target, huh?’ He raised his loaded crossbow, pointed it at Lemmy’s face, and mimed pulling the trigger. ‘Click.’

‘Oh, you’re funny.’

Yuri said, ‘These “trees” look like stems to me, like the stems back in the Puddle. Just bigger.’

Martha rubbed a nearby smooth trunk. ‘So they do. I do know forests, a little. On Earth lots of different species have produced “trees”, palms and ferns for instance. It’s a common form, if you have a situation where you need nutrients from the ground and have to compete for light from the sky. So it’s no surprise to see similar forms here. A universal strategy.’

Onizuka sneered. ‘You’re an expert, right?’

She faced him calmly. ‘If you’d ever bothered to speak to me instead of staring at my chest the whole time, you’d know I once made my living out of forests. My grandfather, probably back in your time, Yuri, was a researcher attached to one of the great logging corporations in the final days. He sent cameras in to capture images of the last rainforests and such before they were scraped off the planet.’ She grinned. ‘Eco porn. Fleeing Stone Age-type inhabitants, the huge trees crashing down. My family packaged and repackaged the stuff for years; the more remote it got in time the more exotic it seemed. A real money-spinner, for us. People cheer and place bets on who survives.’