When: 2010-05-17
Collection location: Madison, Dane Co., Wisconsin, USA [Click for map]
Images
| User’s votes are weighted by their contribution to the site (log10 contribution). In addition, the user who created the observation gets an extra vote. | |||||||||
| Vote | Score | Weight | Users | ||||||
|---|---|---|---|---|---|---|---|---|---|
| I’d Call It That | 3.0 | 0.00 | 0 | ||||||
| Promising | 2.0 | 4.57 | 1 | (kitparrish) | |||||
| Could Be | 1.0 | 0.00 | 0 | ||||||
| Doubtful | -1.0 | 6.23 | 1 | (Andrew) | |||||
| Not Likely | -2.0 | 0.00 | 0 | ||||||
| As If! | -3.0 | 0.00 | 0 | ||||||
| Overall Score sum(score * weight) / (total weight + 1) |
0.25 | 8.21% | |||||||
| User’s votes are weighted by their contribution to the site (log10 contribution). In addition, the user who created the observation gets an extra vote. | |||||||||
| Vote | Score | Weight | Users | ||||||
|---|---|---|---|---|---|---|---|---|---|
| I’d Call It That | 3.0 | 6.23 | 1 | (Andrew) | |||||
| Promising | 2.0 | 0.00 | 0 | ||||||
| Could Be | 1.0 | 0.00 | 0 | ||||||
| Doubtful | -1.0 | 0.00 | 0 | ||||||
| Not Likely | -2.0 | 0.00 | 0 | ||||||
| As If! | -3.0 | 0.00 | 0 | ||||||
| Overall Score sum(score * weight) / (total weight + 1) |
2.59 | 86.17% | |||||||
Comments
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I’ve just gotten an old book on tree diseases and have come across a photo of Hypoxylon mammatum (or H. pruinatum) – Hypoxylon Canker of aspen. It looks like this one. I’ve compared all the images I could find of this Hypoxylon and Megaspora verrucosa – the fungus wins. I actually have a specimen (from different location) that can be tested.
And thanks for putting a name to it, Chris!
This is a lichen with a whitish, crustose, warty (verrucose) thallus, growing on poplar bark, without soredia or isidia, and with abundant blackish immersed apothecia, which suggests Megaspora verrucosa. Thompson (2003, p.140) says “Apothecia immersed in areoles, appearing like Pertusaria, disk deeply concave, at first osteolate, becoming broader with a thin darkening border around the mouth within the thalloid margin; disk black.”
Compare with these photos of Megaspora verrucosa by the Stridvall’s, and a few more photos of Megaspora verrucosa by Einar Timdall.
Reference:
Thompson, 2003, Lichens of Wisconsin
I think it might be a lichen. It was growing on the poplar tree (see bottom photo)
Congratulations on finally getting to the bottom of this. I agree, this does look a lot like Hypoxylon mammatum… more than Megaspora.