-- IIRC, the book starts off with an attempt to steal seed of the triffids from a research institute: the plane carrying a case of seed gets shot down, the case being disrupted and the thistledown-like seeds scattered on the jet stream to all corners of the earth. The triffid farms are decades old by the time of the meteor shower. My memory could be faulty, I read the book 35 years ago, but I do remember that the plot of the film, when I saw it some years later, was significantly different from the book, with the triffid seeds arriving in the meteor shower. Malcolm Farmer