It has been disputed that there are a number of ‘largest living organisms’ on earth, but i want to know which one is REALLY the largest, for once and for all. Among the ones i have heard disputed have been a grove of aspen trees in Washington state, the great barrier reef in Australia, or amazingly large fungi. So once and for all, what is it?
~J
Once and for all, it depends on your definition of “large”.
Send in the clones …
You aren’t going to get a definitive answer. It depends on whether you consider clonal colonies single individuals. You might also throw in a 3000 trunk Banyan tree in Sri Lanka which may qualify if you’re going to disallow the others as not really being the same individual.
The aspen grove in question is in the Wasatch Mountains in Utah, actually, in the Fishlake National Forest:
http://www.extremescience.com/aspengrove.htm
There are a couple of large fungal colonies contesting the claim.
Personally, I think all of these things are large groups of separate organisms. I like the banyan, which is undeniably one tree occupying something like a dozen acres:
There’s a fungus among us: http://www.vgspc.com/newsy/armillaria.htm
…but if you’re searching for the largest tree, the banyan tree mentioned in India only has the largest base. The General Sherman tree in Sequoia National Park holds the record for total volume.
http://features.learningkingdom.com/fact/archive/1998/01/06.html
IMHO The fungus wins.
Someone earlier said that it depends on what the definition of “large” is. I think it depends on what the definition of “individual organism” is. The key word is ‘individual’. IMHO, if you can take a thing and cut it in half and both halves go on living, then the thing was not an “individual organism”.
So, if you cut the General Sherman tree down the top half dies and therefore General Sherman is an individual organism. On the other hand, if you cut one of these giant fungi in half (with a vertical trench, for example), both halves would continue on their merry way therefore not and individual.
As for the banyan tree, it would depend on which way you cut it. If you cut it horizontally, the top half would die but if you cut it vertically, both halves might very well live.
Using this definition, it looks like GS is still boss.
The largest organism there is, is the Sentient Carpet Fern of Bota Chi. Since it hasn’t been discovered yet by Earth People it doesn’t count.
It was until you cut it in half. 
It seems to me that if the organism all has the same DNA and shares resources( nutrients, water, energy via roots, shoots, veins, whatever) then it’s one thing until you seperate it. Is a cell not an individual if it is capable of undergoing mitosis?