July 02, 2008

Wachusett Wednesday

My regular day of field work at Wachusett was cut short by a thunderstorm today. Still, I had enough time to find some great specimens, and I even had company today even though nobody accompanied me to the field.

This pair clearly aren't fungi, but I spent a good deal of time near them. It's a mated pair of deer and they were very curious about me. They seemed to be following me for about an hour, though they never got too close. The female seemed to like it when I talked; she'd perk up her ears and sniff at the air and a couple of times began walking toward me. The deer never got closer than about ten feet, though. I wonder what they were thinking.
This is Amanita flavoconia; it could easily be confused with Amanita flavorubescens, which I found last week. That's probably just as well since both are likely toxic. Aside from some different microscopic features, though, the stipe of A. flavoconia doesn't change color when bruised as it does in A. flavorubescens. The volva of this mushroom is bright yellow and crumbles when handled.
This is also Amanita flavoconia, but an immature basidiocarp. The warty material on the caps of these specimens is the remnant of the universal veil; Amanita grows from a sort of egg, you see. The intensely yellow color of the universal veil remnants on A. flavoconia give it its colloquial name — "yellow patches."
Another Amanita, but quite different from the others. This is Amanita fulva and is a member of a section of the genus whose members are generally edible. Closely related to Amanita caesara, A. fulva is considered a delicacy in some quarters. Misidentification could prove fatal, though. I've tried several of the Amanitas from this group, though, and they are quite good. Most of the members of this section have orange or red tones, a slightly umbonate cap when young and no anulus (ring) on the stipe. The umbo is darker than the rest of the pileus, the margin of which is usually deeply striate. A. fulva has a vaginate volva, terminology that no doubt reflects what mycologists think about when they aren't trying to identify mushrooms. All it means is that the little cup at the base of this mushrooms stipe is membranous and formed like a sac but is narrow, fitting relatively tightly over the stipe. It's still more fun to have an excuse to say "vaginate volva," though.
This unassuming little wood decomposer is Crepidotus applanatum. It looks like a polypore from the top, but if you look closely at the photo you'll notice that it has gills. It is sometimes confused for the very tasty oyster mushroom, Pleurotus ostreatus. Unlike that choice edible, though, C. applanatum is not at all good tasting. It's toxic, but like many toxic things it tastes quite bitter. I doubt anyone would actually choke one of these down, no matter how convinced they'd previously been that it was an oyster mushroom. To avoid ruining dinner, you can always take a spore print. P. ostreatus has a gray to lilac print, whereas C. applanatum has light brown spores. If one examines the cuticle closely there's a definite difference in texture. C. applanatum's is minutely felt-like, whereas P. ostreatus is smooth.
I mentioned last week that there's good evidence that the genera Tylopilus and Leccinum aren't monophyletic and that new genera are likely to be created eventually. This mushroom is an example of the latter genus (for now). It was a difficult one to identify to species, even for our lab's Boletales expert. After a good deal of effort, though, it appears to be either Leccinum snellii or something extremely close to it.
Leccinum species are identified in part by the discoloration that results when the mushroom is cut. The flesh in some turns black, in others it turns brown, and in this one it turns deep pink except at the base, where it turns blue. Other discolorations occur when chemicals are applied. The flesh in the pileus turns blue in FeSO4 and brown-yellow gradually fading to a smoky color in KOH. The tubes bruise dark yellow-brown when bruised as well. You can always spend some time measuring spores, too. You can burn up a good hour or more trying to identify a Leccinum. I know I did. For most folks, though, it's a purely academic question. Almost all of them are good edibles and none are toxic. Some just don't taste good.
Teach the controversy! Some mycologists call this fungus Pluteus admirabilis; others call it Pluteus leoninus You see, P. admirabilis has a yellow stipe with a white base. The mushrooms in these photos clearly have a white stipe with a brown base, and that should make it P. leoninus. However, P. leoninus is solely European in geographic range, and this mushroom is growing in Massachusetts. So which is it? I'm erring on the side of conservative taxonomy and calling it Pluteus admirabilis until someone demonstrates a consistent molecular difference between the fungus with the white-stiped fruiting body and that with a yellow one. Maybe someone else will decide to call it P. admirabilis var. leucostipes and piss all the Pluteus specialists off. That will not be me. I'm jujst happy to see a Pluteus that isn't a boring shade of brown or gray.

You know, if mycologists can't agree on an important detail like this, how can anyone be sure that fungi exist? Those aren't mushrooms, they're god-hats!
In a matter of days, all of the purple tones will vanish from Trichaptum biforme and it will become a drab, grey to pallid, drab little thing like this. I guess it happens to the best of us. This is also a good example of convergent evolution. T. biforme looks quite a bit like Trametes versicolor, the common turkey-tail. In reality, they're about as closely related as you are to your dog... or even your pet bird. Similar environmental pressures over long periods of time have resulted in both fungi hitting on a similar solution in terms of the general shape of their fruiting bodies, but there are numerous less-obvious differences, too. The fungal kingdom is rife with examples of such convergences; the familiar cap-and-stem morphology of mushrooms has evolved independently at least six times and quite possibly more, for instance.

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