“Yes,” Phyllis said. “But will they find us?”

Sax shrugged. “The beeper leaves a directional record.”

“But the wind! Visibility may go right down to nothing!”

“We’ll have to hope they can deal with it.”

The crevasse extended to the east like a narrow low hallway. Sax ducked under a low point, and shone his headlamp down the space between ice and rock; it extended for as far as he could see, in the direction of the east side of the glacier. It seemed possible that it might reach all the way to one of the many small caves on the glacier’s lateral edge, so after sharing the thought with Phyllis he set off to explore the crevasse, leaving her in position to be sure that any searchers who found the hole would also find someone at the bottom of it.

Outside the glary cone of his headlamp’s beam, the ice was an intense cobalt blue, an effect caused by the same Rayleigh scattering that blued the color of the sky. There was a fair amount of light even with his headlamp off, which suggested that the ice overhead was not very thick. Probably the same approximate thickness as the height of their fall, now that he thought of it.

Phyllis’s voice in his ear asked if he was all right.

“I’m fine,” he said. “I think this space might have been caused by the glacier running over a transverse escarpment. So it very well might run all the way out.”

But it didn’t. A hundred meters farther on, the ice on the left closed in and met the ice over the rockface to the right, and that was it: dead end.

On the way back he walked more slowly, stopping to inspect cracks in the ice, and bits of rock underfoot that had perhaps been plucked from the escarpment. In one fissure the cobalt of the ice turned blue-green, and reaching into it with a gloved finger, he pulled out a long dark green mass, frozen on the surface but soft underneath. It was a long dentritic mass of blue-green algae.

“Wow,” he said, and plucked a few frozen strands away, then shoved the rest back into their home crack. He had read that algae were burrowing down into the rock and ice of the planet, and bacteria were going even deeper; but actually to find some buried down here, so far from the sun, was enough to make one marvel. He turned off his headlamp again, and the luminous cobalt blue of the glacial light glowed around him, dim and rich. So dark, so cold, how did any living thing do it?

“Stephen?”

“I’m coming. Look,” he said to Phyllis when he returned to her side, “it’s blue-green algae, all the way down here.”

He held it out for her to look at, but she only gave it the briefest glance. He sat down and got out a sample bag from his thigh pocket, and put a small strand of algae inside, then stared at it through his 20x magnifying lenses. The lenses were not powerful enough to show him all he wanted to see, but they did reveal the long strands of dentritic green, looking slimy as they thawed out. His lectern had catalogs with photos at similar magnifications, but he couldn’t find the species that resembled this one in every detail. “It could be nondescript,” he said. “Wouldn’t that be something. It really makes you wonder if the mutation rate out here is higher than the standard rates. We should work up experiments to determine that.”

Phyllis did not reply.

Sax kept his thoughts to himself as he continued to search through the catalogs. He was still at it when they heard scratchy squeals and hisses over their radio, and Phyllis began calling out over the common band. Soon they could hear voices on the intercom, and not long after that, a round helmet filled the hole overhead. “We’re here!” Phyllis cried.

“Wait a second,” Berkina said, “we’ve got a rope ladder for you.”

And after an awkward swinging climb they were back on the surface of the glacier, blinking in the dusty fluctuating daylight, and crouching over to meet the gusts of wind, which were still powerful. Phyllis was laughing, explaining what had happened in her usual manner — “We were holding hands so we didn’t lose each other, and boom, down we went!” — and their rescuers were describing the brute force of the strongest gusts. All seemed back to normal; but when they got inside the station, and took off their helmets, Phyllis gave him a brief searching glance, a very curious look indeed, as if he had revealed something to her out there which had made her wary — as if he had somehow reminded her of something, down in that crevasse. As if he had behaved down there in a manner which gave him away, without hope of contradiction, as her old comrade Saxifrage Russell.

Through the Northern fall they worked around the glacier, and saw the days grow shorter, and the winds colder. Big intricate ice flowers grew on the glacier every night, and only melted at the edges briefly in the midafternoons, after which they hardened and served as the base for even more complex petals that appeared the next morning, the small sharp crystalline flakes bursting away in every direction from the larger fins and tines beneath. They could not help crushing entire fractal worlds with every step as they crunch-crunched over the ice, looking for the plants now covered in frost, to see how they were coping with the coming cold. Looking across the bumpy white waste, feeling the wind cut through one of the thicker insulated walkers, it seemed to Sax that a very severe winterkill was inevitable. ‘

But looks were deceptive. Oh there would be winterkill, of course; but the plants were hardening, as the overwintering gardeners called it, acclimatizing to the onset of winter. It was a three-stage process, Sax learned, digging in the thin hard-packed snow to find the signs. First, phytochrome clocks in the leaves sensed the shorter days-and now they were getting shorter fast, with dark fronts coming through every week or so, dumping dirtywhite snow out of black low-bellied cumulonimbus clouds. In the second stage, growth ceased, carbohydrates translocated to the roots, and amounts of abscisic acid grew in some leaves until they fell off. Sax found lots of these leaves, yellowed or brown and still hanging from their stems, hugging the ground and providing the yet living plant with some more insulation. During this stage water was moving out of cells into intercellular ice crystals, and the cell membranes were toughening, while sugar molecules replaced water molecules in some proteins. Then in the third and coldest stage, a smooth ice formed around the cells without rupturing them, in a process called vitrification.

At this point the plants could tolerate temperatures down to 220°K, which had been approximately the average temperature of Mars before their arrival, but was now about as cold as it got. And the snow which fell in the ever more frequent storms actually served as insulation for the plants, keeping the ground that it covered warmer than the windy surface. As he dug around in the snow with numbed fingers, the subnivean environment looked to Sax to be a fascinating place, especially the adaptations to the spectrally selected blue light that was transmitted through as much as three meters of snow-^-another example of Rayleigh scattering. He would have liked to study this winter world in person for the entire six months of the season; he found he liked it out under the low dark waves of cloud, on the white surface of the snowy glacier, leaning into the wind and stomping through drifts. But Claire wanted him to return to Burroughs, to work with the labs there on a tundra tamarisk they were close to succeeding with in the Mars jars. And Phyllis and the rest of the crew from Armscor and the Transitional Authority were going back as well. So one day they left the station to a little crew of researcher-gardeners, and got in a caravan of cars, and drove back south together.

Sax had groaned when he heard that Phyllis and her group would be going back with them. He had hoped that mere physical separation would end the relationship with Phyllis, and get him away from that probing eye. But as they were going back together, it looked like some sort of action would have to be taken. He would have to break it off if he wanted it to end, which he did. The whole idea of getting involved with her had been a bad one to begin with; talk about the surge of the unexplainable! But the surge was over,