365 Urban Species. #071: Irpex lacteus

[urbpan]

Urban species #071: Irpex lacteus


photo by cottonmanifesto

If you see what looks like white paint splashed on dead wood, chances are you're seeing the fungus Irpex lacteus. While many of the fungi profiled in this series have been host-specific, Irpex can infect almost any kind of wood. It's the only fungus I have found growing on the hardy weedlike Tree of Heaven (Ailanthus altissima), and can even grow on bamboo. In one exceptional and bizarre case it infected a human being.

This fungus is one of a few species sometimes called "crust" or "parchment" fungi. The fruiting body emerges from the wood as a thin spreading layer on the underside of the wood, or the side. A small lip or shelf forms over the crust when it forms on a vertical piece of wood, to protect the spore-producing surface from rain. The spores are produced from a texture resembling hundreds of tiny teeth. The crust generally grows in fall, but persists year-round.



Detail of crust shown above, growing on dead cherry wood.


Tree of heaven infected with Irpex


Detail of above.


Irpex crust on burnt European beech


Detail of spore-bearing surface.

Comments

[artemii.livejournal.com]

i see this all the time on dead cherries up here (since cherries are so popular with cambridge and somerville's tree planters). to me it looks kind of like a squashed piece of chewed gum :)

[urbpan.livejournal.com]

Those cherry trees are very beautiful--for about a week each year. Not to put down trees or anything--cherries provide food for birds, too--but I think they are overplanted. I'm a maple lover, myself.

[artemii.livejournal.com]

in theory i love maples. in actuality they are tied with ragweed my biggest pollen allergen (i could tell they were blooming this weekend without even looking up because my sinuses are so inflamed).

i think they like ornamental cherries because they don't fruit (no mess to clean up) and they tend to stay compact in size. too bad they're a terrible, terrible, terrible tree for an urban environment, and tend to die even more quickly than other urban trees as a result.

[ex-wellread.livejournal.com]

I've seen trees like that my whole life and never given it any thought (top photo only). I guess I just thought it was just the way trees are.

*hides face*

I'm such a city slicker.

[urbpan.livejournal.com]

And now you know what it is! I have done my job. :)

Just so you know, Irpex is only one of a few species of crust fungi. Stereum can also look like an underside crust. The important thing is that they are all doing the same thing: producing spores so that the fungus that is living inside the dead (or dying) wood can reproduce.