Bedlam Planet by John Brunner

left it there and went back to sleep. In the morning it was gone.
    Later, he woke one day at dawn to find the air full of iridescent bubbles, and jumped up in excitement, realising that the Asgard bladderwrack was fruiting. He had seen it on his first visit, but only once then and not since his return. He ran to the edge of the nearest promontory and stared across the sea. Its surface was blistered with millions of little pustules; every few minutes a convulsion went through them, and another horde detached themselves and floated up into the sky.
    Yoko had explained that to him, too: during the previous night, the drifting mass of bladderwrack wouldhave contracted its hollow fronds, forcing quantities of gas that consisted of nearly eighty per cent hydrogen into the bladders which gave its name. When the topmost layer was full, the gas started to collect in the next, and so on, until it began to distend the tenuous membranes connecting the bladders. These tore, and freed the pearly bubbles he was watching.
    He reached out and caught one. It rested on his palm for a few seconds, then collapsed with a puffing noise. There was something in human skin-secretions which attacked its tissue.
    In an hour there was nothing left except some shrivelled black rags of organic matter, which gave off a foetid stench and drove him away.
    There were virtually no other landmarks during his trip, and yet he was far from bored. Isolation suited him. After the first few days, he no longer felt burdened with the need to think. His pattern of behavior became automatic. He let the boat carry him to the next island on the schedule, chose a camp-site, located any visible clues he could to the area where he was expected to search, such as changes in the colour of the ground or remnants of ancient vulcanism, and set to work contentedly enough, scrabbling among rock-screes and probing clay-beds with his portable sonar unit.
    When he did discover diamonds, after only thirteen days of travelling and in exactly the sort of place where the computers had told him to look, he felt disappointed. He looked in puzzlement at the slightly rounded pebbles his instruments assured him were really diamonds, although they looked dull and uninteresting. One of the half-dozen or so he had picked up was nearly the size of his little fingernail, a good gem-quality stone, and the others were like grains of rice.
    Mechanically he replaced them one by one in the test-slot of his crystalline analyser, noted the readings, and read them off across the table of values stamped on the device’s housing. Diamond. Unequivocally. Therewas absolutely nothing he could have confused them with.
    He stretched out his time at the spot as much as he could. Using his machete, he blazed a route from his landing-site through the vegetation by scoring the bark of woodplants. He marked the beach with arrows made of white pebbles, well above the high-tide level. All that was completely superfluous; he needed to do no more than call base at his usual time and ask them to fix his location with two of the orbiting weather satellites. Then, if necessary, any other member of the colony could come here and locate the diamond deposit in less than half an hour.
    Sighing, he sat down on a rock overlooking the beach, passing the largest of his diamonds from hand to hand, and wondered about reporting his find immediately. It would only take him a day and a half to get back to base in a straight line from here, and he didn’t want to go back so soon. On the other hand, his purpose accomplished, he lacked the incentive to drift on aimlessly.
    Perhaps he could let it depend on who answered his evening radio call. Mostly, since he set out, he had confined himself to a couple of curt sentences indicating that he was well and continuing the search. Once or twice a garrulous person had been at the other end of the radio link: Kitty, for instance, had been in the radio room by chance after running a routine check on