Are mushrooms vegetarian or non-vegetarian?

[mooks]

Please follow up with any links if any exists. Thank you very much!
A better way to put the above question is, are mushrooms a vegetarian cuisine or a non-vegetarian cuisine?
Although I am getting a lot of answers, there is no specific point to say that vegetarians can eat it without doubt! Nothing that says it is a non-vegetarian item and vice-versa.

[GURU]

Mushrooms are suitable for vegetarians, as they are a fungus. In fact, Quorn, a type of vegetarian meat substitute is also made from a type of fungus, known as a mycoprotein.
You can find out which foods are vegetarian/non-vegetarian from the vegetarian society in your country. Below are links to the relevant pages of the UK Vegetarian Society about the definitions of vegetarianism etc. There may be other useful information to you if you have a look around the site.