The Day of the Triffids Author:John Wyndham Until a few short hours ago, before the sky exploded into a shower of flaming green hell, the triffids had been regarded as merely a curious and profitable form of plant life. Now these shadowy creatures became a crawling, killing, nightmare of pain and horror. — Madness hung in the air, fear lurked in every side street, death hovered in every d... more »oorway. Stripped of civilized veneer by terror and desperation, the handful of surviving humans began to turn on each other. And all the while, the triffids watched and waited.« less
I remember this as a movie (not a very good one at that) with a quite different ending. To annihilate ourselves this time, we don't invent a better bomb, we create a plant: one that provides a new and superior source of vegetable oil. Great! Except that it is can transplant itself, reproduces quickly, has a form of intelligence, and in its adult stage is a carnivore. Wow! Now it has spread all over the world and is taking over. And, it seems, that only bumbling old British ingenuity can stem the tide. But, can they eradicate it? This has to be one of the all-time Sci-Fi classics.