There are berries in the northeast that look much like cranberries, but as a kid I was told they are deadly poisonous. Regardless of the accuracy of that warning, the basic concept should hold: if you don't know what it is, don't assume it is safe.
Wild mushrooms are harder to identify. Other than the few I can readily identify on sight, I use an identification guide. There have been several cases of people (almost always from the Far East) inadvertently dying after eating death caps (Amanita phalloides) which I've read taste delicious but are fatal, and can take days to kill:
http://www.iwcp.co.uk/news/second-mushroom-victim-critical-i...
http://www.abc.net.au/news/2012-01-04/two-die-from-death-cap...
http://www.abc.net.au/news/2012-06-08/woman-dies-after-eatin...
They mistake them for paddy straw mushrooms (Volvariella volvacea) which look identical and are used in Chinese and Thai cuisine. They can be distinguished by spore colour but a better way is to check it came out of a tin before eating them.
I live in Tasmania and have been meaning to find an edible field guide to mushrooms or some such. Mushrooms here in Launceston are frequently popping out of the ground in my front and backyard and on the grass verges by the road, and if you walk anyway in the national parks and state forests you're up to your knees in mushrooms.
Would love to know if any of them are edible.
You need an identification guide for your area (Tasmania, or perhaps all of Australia). Unless you can safely identify the species, you cannot be sure it is safe to eat, and should discard it. Identification is usually done using a dichotomous key, which involves checking for the presence or absence of a characteristic (which involves understanding some jargon), then another, until you're down to genus level. Then you check visually to identify the species. It's a bit like an expert system, except printed in a book.
In some countries in continental Europe, you can take wild mushrooms to a pharmacist for identification.
Better than just an identification guide ...
It just baffles me that a reasonably intelligent person would eat unknown fruit found in the wild in a foreign country.
The time for eating unidentified fruit is when you are dying of starvation.
My father spent the last ten years of his career as an ethnobotanist (having previously been a government archaeologist) and his advice was increase the amount by doubling it with each subsequent test. Going from one piece of a leaf to 1/4 cup is a little bit too much of a leap, IMHO.
No, actually they would have probably improved human knowledge after conducting the autopsy on your body and examined what you had carelessly ingested... ;) j/k
It's really more of an advisory.
I think I've been pretty lucky; however, I did always avoid (wild) mushrooms...
https://en.wikipedia.org/wiki/Taxus_baccata
Looks like the berries are technically edible, minus the seeds...
That said it's still stupid, if you aren't starving, to risk this.
[1] http://minnesota.cbslocal.com/2013/02/17/mn-man-determined-t... [2] https://en.wikipedia.org/wiki/Angiostrongylus_cantonensis
However, the skin of mangos contain trace amounts of a toxin similar to that in poison ivy/oak, and some people can react to it in their skins--though not life threatening.
There are some things in Hawaii which can kill you. If the article author had taken the same bite from the be-still fruit (Cascabela thevetia), she'd most likely be dead. A couple of others too: castor bean (ricin) and black-eye Susan beans (can't remember the exact name). They're all plants that were imported as ornamentals and are now spreading invasively. Edited to add: some native plants can be dangerous as well: all parts of the taro plant must be cooked to get rid of oxalic acid cristals which will severely irritate your mouth and throat.
The author of the original article is truly a Darwin Award seeker, something about tropical vacations make people leave their brains at home--they take the tropical paradise meme far too literally. Though I guess we now have an accurate medical paper on the effects of the manchineel.
I absolutely share your astonishment. It seems reckless beyond all justification, especially given that this incident occurred in a land foreign to the author. I'd like to give the author props for having the courage to write about it, but something about the "warning to the world" tone at the end makes me suspicious that he or she doesn't know most people wouldn't do this.