this is primarily directed toward Blast as he seems to know a great deal about using wild plants for food and other purposes. However, information from anyone is very welcome.

I travel extensively to various parts of the world. I have seen many similar types of plants and trees in many parts of the world. Is there a book, school, method or any other resource for learning about plants and their uses without focusing exclusively on a particular region? If a worldwide resource is not available, is there something which can be used for a broad region (continent, hemisphere)?

I appreciate all the help.

There are two books I would recommend to you to meet your needs. The first is Thomas Elpel's Botany in a Day and the second is the U.S. Army's Complete Guide to Edible Wild Plants.

Thomas Elpel's book is designed to help you identify plants based on the shared characteristics of the different plant families. Each day you learn the identifying markers of a new class of plants, by the end you can quickly tell from a glance what family a plant is in regardless of where in the world you are. Knowing this makes determination of a plant's edibility much easier. For a better taste (ha ha ha!) of Elpel's book check out his website Wildflowers and Weeds.

I think the U.S. Army book will also be useful to you as it covers common edible plants world-wide, not just the northeastern part of the USA.

Hope these help.
-Blast

Disclaimer: purchasing either of those books from the links I posted will result in me earning about 24 cents per book.

Thanks Blast, that is exactly what I was looking for. I am surprised I had never seen the Army book before. It is a skill I really need to work on.

You asked for methods... Here's a method for testing plants on the fly...

1) Identify an abundant plant. The length of the testing process makes this pointless if you
don't have enough of the plant on hand to chow down on.
2) Consider each part of the plant as a separate entity requiring its own test. On some plants,
the leaves may be edible but the roots poisonous. Don't assume that one part passing the test
means all parts are edible. Plants should be broken down into roots, stems, leaves, buds,
flowers and berries. Again, use the abundance criteria here. If there are a lot of a type of
plant available and a lot of leaves on that plant, test only the leaves at first. Also choose
healthy plants. Avoid rotting or bug-infested plants and three-leafed plants such as poison
ivy.
3) Smell the plant parts. Avoid anything that smells like almonds or acid. Also avoid anything
that oozes a milky substance. These are not certain indicators of toxicity, but far too often
imply the plant is not edible so best to avoid them entirely.
4) Next rub the plant against a sensitive part of your skin (not your lips) such as the inside of
your elbow or behind your knee. Make sure to rub it in good so that the juices get on your
skin. If you have no immediate reaction, hold the plant against that part of your skin for
10-20 minutes. Now wait for at least 8 hours. If you do not have a reaction, move on to the
next test.
5) Prepare the plant part as you plan to eat it (raw, boiled, etc.) Touch a small part of the
plant against your lip for three minutes. If you do not experience burning, stinging, tingling,
itching or other discomfort, move on to the next test.
6) Place another portion on your tongue and leave it there. DO NOT CHEW OR
SWALLOW. If you experience no adverse symptoms after 15 minutes, chew the piece well
and hold it in your mouth for another 15 minutes. Again, DO NOT SWALLOW. Assuming
you've still experienced no adverse symptoms, swallow the piece. Adverse symptoms consist
of burning, itching, numbness, swelling, tingling or stinging.
7) Wait 8 hours. If all is well after 8 hours, eat a small portion of the plant. Not a meal, just a
very light snack portion of less than a ½ cup and wait another 8 hours. If you still feel fine,
you can assume the part of the plant you have been testing is ok to eat. If you experience any
ill effects at any point after ingesting the plant, immediately induce vomiting and consume as
much water as you can.

I got the above from http://www.breakawayadventure.com/Survival%20-%20Plants.html

That is the normal method of testing for consumption when you don't know the plants. It is a good method. What I am trying to do is learn to recognize and identify the types of plants that are useful for many different things (cordage, medicines, foods, etc.). Where I am week is in the general knowledge of what plants are useful for what and how to find them. I am also trying to learn what types, or families, of plants are found in what regions where I travel so I can learn what to expect to be able to find. Then I will be learning how to process and prepare them for use. It is a bit of a long term thing, but I was cursed with the curiosity of a 5 year old and feel that a day I don't learn something is a day wasted. Thanks for the site!

I don't have time to go into detail but this is actually a LOUSY way to identify edible plants.

I'll write more after tonight's face-to-face meeting of ETS members here in Houston.
-Blast

The funny thing is, I can identify quite few wild plants. Unfortunately, the ones I can typically find and identify aren't usually edible.

With that said, on a recent hike, I think I did find some wild raspberries though. I wasn't going to try them at the time, because with my luck they would be some kind of poisonous raspberry-resembling plant and the kids I was hiking with would have had to carry my heavy butt out of there, but I'm pretty sure they were raspberries.

I seem to have a number of aquaintances who believe plants "talk" to them about their edible and medicinal properties, whether they identify a plant or not. Their routine includes closed eye exploration of the scent, feel, taste, sound of the plant rubbing on one's cheek and hand, and then open-sensed [including intuitive and spirit based] appreciation of the plant as a whole and how it fits into its environment. Me, I like plant guides.

A lot of survival guides give this method but there are several problems with it. The first is that it's usually presented as what to do if you are lost and starving. However if you read through the directions you will hopefully realize that it will take 1-2 weeks just to examine the roots, stem, leaves, and fruit of one plant and during that time you can't eat anything else as that brings too many variables into play so if you have a reaction you won't be able to tell which plant material caused it.
Second, have you ever tried to hold something in your mouth for fifteen minutes (actually thirty minutes total!) without swallowing anything, especially if you are really hungry?
Third it doesn't test more subtle but deadly poisons such as from pokeweed, many legumes, etc.
Fourth, many poisons are not "contact" poisons but must be consumed to cause injury. At the same there are many plants that contain contact poisons which are easily removed by cooking or other native preparation method.
Fifth, if you do find some unknown, "nontoxic" plant that passes these tests there's still a very good chance that all you do is fill your stomach with matter that you can not digest which can lead to other medical issues, of which "the runs" is the most benign. Imagine a stomach full of grass. Most (not all) grasses will pass these tests but your body can't get any useful nutrition from them. However, filling your stomach with grass can interfere with your ability to digest other nutritional foods if you find some.

Seriously folks, just forget about this method unless you have a platoon of disposable(!) troops on which to experiment. It's bad advice written by armchair experts.

-Blast

good points Blast. Glad you brought that up.

Excellent advice Blast!

Thanks very much, Blast!

Sage advise Blast.

For years, I have seen the same or similar "tests" for poisonous plants all over the web and would never choose this test method no matter how hungry I would be...

There is probably a very good reason for that as the rare and obscure wild edibles are pretty much pointless in terms of calorific or nutritional use for the payback invested in energy terms for processing and collecting. Most 'Wild' edibles worth seeking out aren't really wild, because the plant would have already been exploited, cultivated and used in general agriculture.

Probably the best place to start is gathering knowledge on what you can find, use and exploit out in the wilderness, is down at the local supermarket fruit and veg stall and work backwards in time (a few thousand years) and geography to see if you can find the smaller and less nutritional (energy not vitamins and minerals) version in those 'wild' places.

The other main difference of course, which many Homo Urbanus finds a little difficult to understand is that the seasons play a huge role in the 'wild' foods as the supermarkets don't have seasonal produce anymore as they operate within the global economy.