Eden by Stanislaw Lem

ten," said the Captain. "We've had a rest, so I think we should make another excursion now. In a different direction this time. The Engineer was supposed to prepare the jectors—how is that coming along?"
    "We have five, and all are charged."
    "Good. We went north before, let's try east now. And don't use the jectors unless you have to. Especially if we come across those … doublers, as the Engineer called them."
    "Doublers," the Doctor muttered to himself, as if trying out the name and not liking it.
    "Shall we go?" asked the Physicist.
    "All right. But let's secure the hatch first, to avoid new surprises."
    "Shouldn't we take the jeep?" asked the Cyberneticist.
    "I'll need at least five hours to get it working," said the Engineer. "Unless we postpone the excursion until tomorrow?"
    But no one wanted to postpone it, so they set off around eleven, after preparing their equipment. As if by arrangement—though no one had suggested it—they went in pairs and kept close together; the only man without a weapon, the Doctor, was in the middle pair. Whether the terrain was more walkable or they simply walked faster, they lost sight of the rocket in less than an hour. The landscape changed. There were more and more slender gray "calyxes," which they avoided, and in the distance, in the north, they saw hills that appeared domed and met the plain in steep crags. But the hills ahead of them, as they marched, were covered with patches of vegetation darker than the soil.
    The vegetation rustled underfoot and was the color of ashes. The young shoots, however, were whitish veinlike tubes with small beads growing out of them.
    "Do you know what I miss the most here?" said the Physicist. "Grass, ordinary grass. I would never have thought that grass would be so…" He groped for the word. "…necessary…"
    The sun was brutal. As they approached the hills, they could hear a soughing sound.
    "Strange. There's no wind, but there's the sound of a wind," remarked the Chemist, who was in the first pair.
    "It's coming from higher up," the Captain said, behind him. "Look, those are Earth trees!"
    "They're a different color…"
    "They're two colors," said the Doctor, who had sharp eyes. "They alternate—now they're violet, now blue with yellow highlights."
    The men left the plain and entered a broad canyon with clay walls that were covered with a delicate mist. On closer inspection the mist turned out to be a kind of lichen that resembled loose fiberglass insulation.
    They looked up as they passed the first clump of trees, growing at the edge of a precipice about forty feet above their heads.
    "But those aren't trees at all!" cried the Cyberneticist with disappointment, at the end of the line.
    The "trees" had thick, extremely shiny trunks, as though they had been greased, and multilayered crowns that pulsed rhythmically, darkening, then expanding and paling, letting the sunlight through in a hundred tiny places. This was accompanied by a sound, as though a chorus were whispering, over and over again, "fsss … hhaaa … fsss … hhaaa…" Then they noticed, on the nearest tree, growing out of its twisting branches, blisters as long as bananas and swollen with grapelike excrescences that puffed and darkened, collapsed and paled, puffed and darkened, collapsed and paled.
    "It's breathing," the Engineer murmured. He listened raptly to the sounds that drifted down and filled the canyon.
    "But observe that each has a rhythm of its own," the Doctor cried, excited. "The shorter it is, the faster it breathes! They are … lung-trees!"
    "Let's keep moving!" called the Captain, who was a dozen or so paces ahead of the standing group.
    They followed him. The canyon narrowed, and its floor led gradually uphill, bringing them to a domed rise between two clumps of trees.
    "When you shut your eyes, it's like being at the seashore. Try it!" the Physicist said to the Engineer.
    "I'll keep my eyes open, thanks," muttered the Engineer in reply. He left their line of