Eucalyptus that has a black mould on that can bring on asthma attacks: Bloodwood = cadaga = [url=http://www.flickr.com/photos/thetannykid/205641584/]Eucalyptus torelliana[/url]. Flowers Mar-April.
It is a very common large gum tree.
My tree lopper strongly suggested removing one from our backyard and may have saved me repeat trips to Emergency.