Friday 10 April 2015

Googly Eyes on Dogwood: Schizoxylon alboatrum

Schizoxylon alboatrum ascomycete looks like tiny eyes

For a few weeks now, people all over the internet have been ecstatically posting pictures of their first morels of the year—people who obviously don't live in central Ontario. No morels here. Here there's still plenty of snow in the woods, so I don't expect any Morchella to poke up for at least another couple of weeks. But who cares? Even when I'm still wearing my winter scarf and earmuffs I can find even better things than morels. Well, not better for eating, I admit, but better in the weirdness department. Things like what I found in the alder swamp yesterday: I picked up a long-dead dogwood (Cornus sp.) twig to look at it more closely and it was staring back at me. It was covered in tiny, protruding, ascomycete eyeballs.


1mm tiny ascomycete Schizoxylon alboatrum
Schizoxylon alboatrum fruiting bodies are erumpent and .05-1.0 mm in diameter.

The minute, fuzzy whitish apothecia with shiny black "pupils" were nothing like anything I'd ever seen before—not in real life, not in any book I own, and not on any website. 



Schizoxylon alboatrum erupts through bark
Schizoxylon alboatrum are erumpent—a word that
makes me happy. They erupt through bark.
Schizoxylon alboatrum black centres, fuzzy white
Dried out, Schizoxylon alboatrum look less like eyes and more like
the coconut liquorice allsorts everybody eats last.

I hoped that a bit of work with the microscope might be illuminating, so I sectioned one and had a look. I was, I admit, totally perplexed by what I was confronted with: a bunch of hairs with multiply split ends. It took a few minutes to figure out that the hairs I was looking at were actually extremely long and slender asci (350-400 x 7-8 µm), and the "split ends" were the equally long ascospores working their way out. 


Schizoxylon alboatrum asci, ascospores, paraphyses
Asci, ascospores, and paraphyses all look hairy.

I got on the computer and started googling "filiform ascospores" hoping I'd get lucky. I didn't. My backup at times like this is to go first to the back pages of Fungi of Switzerland: Volume 1 (Ascomycetes), where all the real oddities reside, but the only characters with filiform ascospores did not have fruiting bodies that even vaguely resembled my little "goggly eyes." Which meant I had to go page by page through the asci and spore illustrations in Ellis & Ellis's Microfungi on Land Plants. Finally, on Plate 118, I found a couple of possible genus names to investigate, Stictis (illustration #1243) and Schizoxylon (illustration #1242). 

After another two hours of internet work, I had a name: Schizoxlyon alboatrum. The species epithet is a simple descriptive—albo meaning white, and atrum being black. 


Schizoxylon alboatrum and filiform ascus and spores
A clutch of the incredibly long ascospores of Schizoxylon alboatrum.

I've found reference to it being rare or uncommon, but I don't know if that's true. Maybe if all the people out looking for morels were also keeping an eye out for wee characters like these, we'd find out that they're actually more common than suggested. What's indisputable, though, is that, edibility-wise, they are "without interest"—at least for humans.



References:


The genus Schizoxylon, key & descriptions: Martha A. Sherwood, The Ostropalean Fungi, Mycotaxon 5 (1), 1977. 108-

Schizoxlyon alboatra on MycoDB 

and on Ascofrance











3 comments:

  1. You're a most intrepid explorer of fungi, Jan! I'm sure that I'm one who would have trod right on past, missing the googly eyes altogether. Quite fascinating!

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  2. These ascos are stunning. I have to say your excellent shots of the microscopy has inspired us to set up a savings fund for our own trinocular microscope. Thanks for posting.

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