Do you remember Andy Hertzfeld? He was the author of a huge part of the original Mac ROM and he discusses the creation of the Apple command logo in this writeup. Turns out that the logo was based on a Swedish symbol used to flag noteworthy attractions at campgrounds. Susan Kare, Apple's bitmap artist, found it in an international symbol dictionary.
So why didn't they just use an Apple symbol? Steve Jobs had had enough. "There are too many Apples on the screen! It's ridiculous! We're taking the Apple logo in vain! We've got to stop doing that!" Neat story to read through, and only one of Hertzfeld's many marvelous Apple reminiscences.
Although the actual proper name of the icon is the Saint John's Cross or St. John's Arms, when describing this key to others, I've called it the "butterfly icon", "squiggle icon", 'propeller icon" as well as "clover." What names have you TUAW readers given to the clover symbol?