had ever grown before.

They were called paper-trees because the bulk of their pulp was used to
make paper--they were of no use whatever as lumber--but they weren't
really trees, and the organic chemicals that were leached from them
during the pulping process were of far more value than the paper pulp.

They were mutations of a smaller plant that had been found in the
temperate regions of Mars and purposely changed genetically to grow in
the Siberian tundra country, where the conditions were similar to, but
superior to, their natural habitat. They looked as though someone had
managed to crossbreed the Joshua tree with the cypress and then
persuaded the result to grow grass instead of leaves. And the
photosynthesis of those grasslike blades depended on an iron-bearing
compound that was more closely related to hemoglobin than to
chlorophyll, giving them a rusty red color instead of the normal green
of Earthly plants.

In the distance, Wang heard the whining of the wind increase, and he
automatically pulled his coat a little tighter, even though he noticed
no increase in the wind velocity around him.

Then, as the whine became louder, he realized that it was not the wind.

He turned his head toward the sound and looked up. For a long minute he
watched the sky as the sound increased in volume, but he could see
nothing at first. Then he caught a glimpse of motion, a dot that was
hard to distinguish against the cloud-mottled gray sky.

What was it? An air transport in trouble? There were two transpolar
routes that passed within a few hundred miles of here, but no air
transport he had ever seen made a noise like that. Normally they were so
high up as to be both invisible and inaudible. Must be trouble of some
sort.

He reached down to the saddle pack without taking his eyes from the
moving speck and took out the radiophone. He held it to his ear and
thumbed the call button insistently.

_Grandfather!_ he thought with growing irritation as the seconds passed.
_Wake up! Come on, old dozer, rouse yourself from your dreams!_

At the same time, he checked his wrist compass and estimated the
direction of flight of the dot and its direction from him. He'd at least
be able to give the airline authorities some information if the ship
fell. He wished there were some way to triangulate its height, velocity,
and so on, but he had no need for that kind of thing, so he hadn't the
equipment.

"Yes? Yes?" came a testy, dry voice