I've heard of a Buddhist story in which the Buddha just holds up a flower and one monk in the audience understands then becomes instantly enlightened. I believe it is a foundational text for Zen Buddhism. Where does this text originate from? What canon or collection of texts is it from? When was it wrote and which tradition(s) does it derive from?
Generally I would just like to know a bit of background to the history, authoring and authority of the text. I have only ever hear to it referred to in secondary sources and never giving a primary reference.