September 13, 2007

Finds from Yesterday's Foray

All of the following fungi were found during my outing yesterday on Wachusett Mountain. I'm planning on going back this weekend, too. The area is one of the most mycologically rich I've ever seen.

Amanita fulva is an edible mushroom, very closely related to Amanita vaginata (AKA grisette). I'm exceptionally sure of the identification of this one because of my access now to microscopic and chemical resources. Remember, don't try this at home; Amanita is the most lethal genus of mushrooms there is. Making a mistake could well be fatal. That being said, I've never eaten A. fulva, though I have tried A. vaginata, which is quite excellent though a bit thin fleshed.
As lethal as a poisonous Amanita is to us, just as deadly to trees are the members of the genus Armillaria. Pictured here is the highly-variable Armillaria ostoyae; it specializes in conifers and particularly enjoys killing hemlock trees, the remains of which this little cluster is growing upon. A. ostoyae is particularly challenging to identify because its coloration and morphology can vary a great deal. Again, access to a microscope helps a lot, but even then there is another member of the genus that is so similar to this one that it can only be distinguished at the molecular level. Fortunately for me, that species has never been reported from Massachusetts.

It's worth noting that Armillaria fungi are the largest organisms on earth. The largest one known is nearly 40 acres across and occupies a rather sizable portion of the state of Michigan!
This tiny fungus was extremely hard to shoot; the fruiting bodies you see in the picture are perhaps 10-15 mm tall. It's a rather important organism, though, because Calocera cornea is a very ancient creature that may itself be basal to, or at least is extremely closely related to the fungus that is the ancestor of, all other wood-decomposing fungi. It's a member of Dacrymycetes, all of which are gelatinous fungi that don't have much organization of their plects (fungi have plects instead of tissues) and are characterized by basidia that resemble tuning forks topped with fat sausages. C. cornea represents a time in fungal evolution when fungi could only decompose cellulose, not lignin, because they only possessed a single peroxidase. Such fungi are known as "brown rotters" because digest the cellulose in wood but leave behind the lignin, which is brown. We've used some snippets of this organism in an attempt to start cultures in our lab and it looks like its taking to life in a petri dish without hesitation; we've already got our first, albeit microscopic, lab-grown hyphae. The plan is to genotype this specimen and attempt to reconstruct its phylogeny in greater detail. Good stuff and a very fortunate find.
This rather unassuming brown mushroom, less than a half inch across, is called Lactarius splendens. Somebody had a sense of humor when they named it, because there's nothing at all splendid about it.
Finding a few pounds of Laetiporus sulphureus, on the other hand, is usually pretty splendid. This specimen was too heavily infested with insect larvae, as it turned out, to be worth eating. No worries; I'll find it again, I'm sure. It seems to be much more common here than it was in Florida, which isn't too surprising as it generally seems to prefer cooler weather for fruiting.
As beautiful as they are, coral mushrooms are among the most difficult to identify to species. This graceful yellow specimen took a couple of hours of chemical and microscopic examination before revealing its identity as Ramaria flavo-saponaria. This is a pretty good-sized specimen; the largest ones can get close to six inches tall, though. The inside of the organism is a random-looking assortment of solid white flesh and greasy, translucent areas. If you drop a little 10% FeSO4 solution anywhere on this coralloid, it will turn dark green in two minutes or less. So do a lot of other similar-looking Ramaria.
This dainty little coralloid is Ramariopsis kunzei. It's quite brittle and must be handled very carefully to avoid being left with nothing more than a handful of fungus-crumbs. It's edible, but I'm not sure why anyone would bother eating it. On the other hand, it's the type species for its entire genus. Our lab has been working with samples from Scandinavia, so we're going to sequence this one as well and see how similar it is along various parts of its genome to its Swedish conspecifics.
Last, and certainly least, we have Scleroderma citrinum, which bears the endearing common name "pigskin poison puffball" because it supposedly looks like pigskin, it's poisonous, and it looks superficially like a puffball. Personally, I think the thing looks more like a swollen testicle from a hepatitis patient, but I suppose that's just me. Looking into the specimen, you can see that it's essentially a bag of purple-black spores. The spores are round, about 8μ in diameter, and are wrinkly on their surface. They also get all over everything; dropping a fully ripened specimen creates a huge puff of dust that will settles everywhere. Drying them can be great fun, since that will often cause them to rupture and discharge their spore mass inside your air dryer, which will then spew great clouds of the stuff for you to find the next morning. Big fun, particularly if you're trying to culture anything else in the vicinity. Never, ever bring one of these babies into a room where its spores might find their way to agar. Instead, dry them somewhere safe and wrap them in a damp Kimwipe before doing so; that seems to keep them from exploding in the dryer.

That's your helpful mycological tip for the day, and a good place to end.

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