When Lane had first seen them from the glider as it hurtled over them, he had thought they looked like an army of giant hands uplifted to catch the sun. Giant they were, for each rib-supported leaf measured fifty feet across. And hands they were, hands to beg for and catch the rare gold of the tiny sun. During the day, the ribs on the side nearest the moving sun dipped toward the ground, and the furthest ribs tilted upward. Obviously, the daylong maneuver was designed to expose the complete area of the membrane to the light, to allow not an inch to remain in shadow.

It was to be expected that strange forms of plant life would be found here. But structures built by animal life were not expected. Especially when they were so large and covered an eighth of the planet.

These structures were the tubes from which rose the trunks of the umbrella trees. Lane had tried to drill through the rocklike side of the tube. So hard was it, it had blunted one drill and had done a second no good before he had chipped off a small piece. Contented for the moment with that, he had taken it to the dome, there to examine it under a microscope. After an amazed look, he had whistled. Embedded in the cementlike mass were plant cells. Some were partially destroyed; some, whole. Further tests had shown him that the substance was composed of cellulose, a ligninlike stuff, various nucleic acids, and unknown materials.

The following day he intended to go back to the tube and blast a hole in it. But two of the men had set out in a tractor on a field exploration. Lane, as radio operator for that day, had stayed in the dome. He was to keep in contact with the two, who were to report to him every fifteen minutes.

The tank had been gone about two hours and must have been about thirty miles away, when it had failed to report. Two hours later, the other tank, carrying two men, had followed the prints of the first party. They had gone about thirty miles from base and were maintaining continuous radio contact with Lane.

“There’s a slight obstacle ahead,” Greenberg had said: “It’s a tube coming out at right angles from the one we’ve been paralleling. It has no plants growing from it. Not much of a rise, not much of a drop on the other side, either. We’ll make it easy.”

Then he had yelled.

That was all.

Now, the day after, Lane was on foot, following the fading trail. Behind him lay the base camp, close to the junction of the two canali known as Avernus and Tartarus. He was between two of the rows of vegetation which formed Tartarus, and he was traveling northeastward, toward the Sirenum Mare, the so-called Siren Sea. The Mare, he supposed, would be a much broader group of tree-bearing tubes.

He walked steadily while the sun rose higher and the air grew warmer. He had long ago turned off his suit-heater. This was summer and close to the equator. At noon the temperature would be around seventy degrees Fahrenheit.

But at dusk, when the temperature had plunged through the dry air to zero, Lane was in his sleeping tent. It looked like a cocoon, being sausage-shaped and not much larger than his body. It was inflated so he could remove his helmet and breathe while he warmed himself from the battery-operated heater and ate and drank. The tent was also very flexible; it changed its cocoon shape to a triangle while Lane sat on a folding chair from which hung a plastic bag and did that which every man must do.

During the daytime he did not have to enter the sleeping tent for this. His suit was ingeniously contrived so he could unflap the rear section and expose the necessary area without losing air or pressure from the rest of his suit. Naturally, there was no thought of tempting the teeth of the Martian night. Sixty seconds at midnight were enough to get a severe frostbite where one sat down.

Lane slept until half an hour after dawn, ate, deflated the tent, folded it, stowed it, the battery, heater, food-box, and folding chair into his pack, threw away the plastic sack, shouldered the pack, and resumed his walk.

By noon the tracks faded out completely. It made little difference, for there was only one route the tanks could have taken. That was the corridor between the tubes and the trees.

Now he saw what the two tanks had reported. The trees on his right began to look dead. The trunks and leaves were brown, and the ribs drooped.

He began walking faster, his heart beating hard. An hour passed, and still the line of dead trees stretched as far as he could see.

Then he stopped. Ahead was an obstacle.

It was the tube of which Greenberg had spoken, the one that ran at right angles to the other two and joined them.

Lane looked at it and thought that he could still hear Green-berg’s despairing cry.

That thought seemed to turn a valve in him so that the immense pressure of loneliness, which he had succeeded in holding back until then, flooded in. The blue-black of the sky became the blackness and infinity of space itself, and he was a speck of flesh in an immensity as large as Earths land area, a speck that knew no more of this world than a newborn baby knows of his.

Tiny and helpless, like a baby…

No, he murmured to himself, not a baby. Tiny, yes. Helpless, no. Baby, no. I am a man, a man, an Earthman…

Earthman: Cardigan Lane. Citizen of the U.S.A. Born in Hawaii, the fiftieth state. Of mingled German, Dutch, Chinese, Japanese, Negro, Cherokee, Polynesian, Portuguese, Russian-Jewish, Irish, Scotch, Norwegian, Finnish, Czech, English, and Welsh ancestry. Thirty-one years old. Five foot six. One hundred and sixty pounds. Brown-haired. Blue-eyed. Hawkfeatured, M.D. and Ph.D. Married. Childless. Methodist. Sociable mesomorphic mesovert. Radio ham. Dog breeder. Deer hunter. Skin diver. Writer of first-rate but far from great poetry. All contained in his skin and his pressure suit, plus a love of companionship and life, an intense curiosity, and a courage. And now very much afraid of losing everything except his loneliness.

For some time he stood like a statue before the three-foot high wall of the tube. Finally, he shook his head violently, shook off his fear like a dog shaking off water. Lightly, despite the towering pack on his back, he leaped up onto the top of the tube and looked on the other side, though there was nothing he had not seen before jumping.

The view before him differed from the one behind in only one respect. This was the number of small plants that covered the ground. Or rather, he thought, after taking a second look, he had never seen these plants this size before. They were foot-high replicas of the huge umbrella trees that sprouted from the tubes. And they were not scattered at random, as might have been expected if they had grown from seeds blown by the wind. Instead, they grew in regular rows, the edges of the plants in one row separated from the other by about two feet.

His heart beat even faster. Such spacing must mean they were planted by intelligent life. Yet intelligent life seemed very improbable, given the Martian environment.

Possibly some natural condition might have caused the seeming artificiality of this garden. He would have to investigate.

Always with caution, though. So much depended on him: the lives of the four men, the success of the expedition. If this one failed, it might be the last. Many people on Earth were groaning loudly because of the cost of Space Arm and crying wildly for results that would mean money and power.

The field, or garden, extended for about three hundred yards. At its far end there was another tube at right angles to the two parallel ones. And at this point the giant umbrella plants regained their living and shining blue-green color.

Lane searched the top of the tube for bare spots where the metal plates of the caterpillar tractors’ treads would have scraped off the lichenoids. He found none but was not surprised. The lich-enoids grew phenomenally fast under the summertime sun.