Insect and Disease ID Quiz

I'm having a hard time with my sense of scale on this one. Is this the bottom of a leaf?

I'm gonna throw out Tubakia leaf spot but I think I have a better guess.
 
that patch of crap came off white oak bark?

40+ YRS embracing that species and i do not believe i ever saw that.

or i was not paying attention, if i did...
 
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patch of crap?

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Fixed your guess, Guy. Seems as good as any so far.

Ok, already, what is it? Very curious.
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It's Hypoxylon canker. Here's a photo by Robert L. Anderson, USDA Forest Service, taken from Bugwood.org

[/ QUOTE ]Your pic in post 323190 had green stuff on the bark, with a couple black patches on top of the green stuff.

Which are you saying is the pathogen formerly known as Hypoxylon (briefly Ustulina, now Kretzschmaeria deusta)--the green stuff, or the black patches? I am a tad skeptical of either--wood decay fungus growing on top of an epiphyte??

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It's Hypoxylon canker. Here's a photo by Robert L. Anderson, USDA Forest Service, taken from Bugwood.org

[/ QUOTE ]Your pic in post 323190 had green stuff on the bark, with a couple black patches on top of the green stuff.

Which are you saying is the pathogen formerly known as Hypoxylon (briefly Ustulina, now Kretzschmaeria deusta)--the green stuff, or the black patches? I am a tad skeptical of either--wood decay fungus growing on top of an epiphyte??

confused.gif


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The black pustules breaking through the bark, is the Hypoxylon. The green are lichens.

Not all Hypoxylon species had a name change to Kretzschaeria. The Hypoxylon genus is still being used.

According to Alexopoulos, Mims, and Blackwell in Introductory Mycology 1996: "Many species of Hypoxylon, as it once was circumscribed, have been placed in other genera (e.g., taxa with bipartite stromata and dark, smooth ascospores with germ slits are placed in Biscogniauxia and Camillea includes forms with pale, ornamented ascospores without germ slits). Only species with flattened or spherical stromata and dark, relatively smooth-walled ascospores with germ slits and lacking appendages now are included in Hypoxylon."

What Alexopoulos, et.al. Say about Kretzschmaria: "Kretzschmaria contains species with flat-topped stomata on short stipes. San Martin Gonzales and Rogers (1993) expressed the opinion that the genus is closely related to some species of Xylaria. It also intergrades with Ustulina in the tropics, and some mycologist have placed that genus in synonomy with Kretzschmaria."

The Hypoxylon isn't growing on the lichen and the lichen isn't growing on the Hypoxylon. I'm sure the lichen was growing on the bark and the Hypoxylon grew through the bark disrupting the lichen.
 
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That first shot didn't look like any hypoxylon I've ever seen. The last shot does though.

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You're right, I took the photo under magnification. I'll add the magnification for scale in the future. My apologies.
 
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