group had discovered the Sirens on a terratype world previously covered only sketchily by mapping teams. They were the planet’s principal life-form, blanketing the landmasses in giant forests. The explorers soon discovered that a kind of euphoria, a pleasurable feeling of being drawn to them, was experienced by anyone coming within a few hundred yards of the pseudotrees. So they began referring to this life-form as the Sirens.
It appeared that the Sirens induced other creatures to become dependent on them, and that even a highly evolved species then degenerated very rapidly to the point of becoming a true parasite, unable to survive away from its hosts. A space scan disclosed that two other worlds in that stellar area were also covered with Siren forests. On those worlds, too, there seemed to be no creatures left which hadn’t become Siren parasites, and the indication was that their original human discoverers
It appeared that the Sirens induced other creatures to become dependent on them, and that even a highly evolved species then degenerated very rapidly to the point of becoming a true parasite, unable to survive away from its hosts. A space scan disclosed that two other worlds in that stellar area were also covered with Siren forests. On those worlds, too, there seemed to be no creatures left which hadn’t become Siren parasites, and the indication was that their original human discoverers