The Three Corner Jack (Emex Australis) according to the CSIRO's Department of Entomology is:
"...originally from South Africa. It was intentionally imported into Western Australia (WA) in 1830 as a vegetable (Cape spinach). Once in Australia, it rapidly spread so that it now occurs throughout Australia's southern-temperate regions. It is an annual weed...".
- CSIRO publication
Searching in Google for Emex australis is probably the best way to find out more about the weed and how to control it. Additionally, CRC Weed Management seems to be a pretty good starting point.
Yes, there sure was. From what I can tell they were a folk band, as mentioned in the profiles for Simon Wells and Leigh Newton. There may be other bands, but I don't know of them. Please let me know of anyone else.
Yes, that's true too. It's by Rex Brereton and is titled Three Corner Jack: A Collection of Country Characters . I have read it and will at some point do a complete review of it. Basically, the book is a photo journey through country South Australia, making a photo record of SA's country characters. It is very real and it's a top read. The book is out of print, but after quite a bit of hunting, I found my copy in O'Connell's Bookshop. Which just goes to show that secondhand bookshops are not only hedonistic fun, but useful as well.
This website uses the phrase three corner jack in a strangely affectionate way. Most locals I've told about this phrase being used as a website address have smiled whimsically, even though all of them, at one time or another, have experienced the horrible stabbing pain associated with stepping on a three corner jack. So, while it definitely means something specific, it also means something about belonging 'here'. Clearly, were I a farmer affected by three corner jacks I would not feel so fondly towards it.
The real reason for using it? It's an Australian phrase and I like it.
"They bloody hurt when you tread on them with bare feet. My childhood was full of ouches from these things."
- grudknows