Notes: I was going to just call these Agrocybe pediades until I looked at the spores.
They were brown and large, approx. 15.0-16.1 X 10.0-11.0 microns with an apical germ pore.
Agrocybe pediades var. platysperma is noted in MD as having larger spores but couldn’t find any details.
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and that is all I claimed. Technically it could be A. pediades but I think it is equally likely to be something else. Irene noted another new species and I still like A. platysperma. It is a valid, recognized species from California. Besides the spores the cap description also works.
And in the framework of MO, if someone else has an opinion, He/she can vote and Mike Wood in this case tilted the argument in favor of A. platysperma. Not crazy, just Democracy in action.
Unfortunately, I did not save any specimens. I’m too old to start another career as an Agrocybe specialist.
Not sure you can put a new name on this, just from the spore measurement. The spore size you’ve got there pretty much falls right into the size for Agrocybe pediades. Reaching back to some name no one else has used… I’m not sure about that one, without any more evidence to go on…
If you are just reacting to the fact that this one doesn’t look like the other one… and you need two names… I think you’d have to go with this one being Agrocybe pediades, and the other one being some other name. Unless you have something else to go on?
At least you can’t vote that Agrocybe pediades is not likely… it certainly is likely…
Did you take a look at the gills in the microscope too?
A new species with broad spores like the other pediades forms, is Agrocybe ochracea:
Pleurocystidia present (absent in pediades). Cap 10-30 mm, convex, viscid, smooth, ochraceous yellow, with darker centre and paler margin; gills brown; stem 30-50 × 2-4 mm, pale yellowish; smell and taste farinaceous. Sp 11.5-15.5 × 8-10(-12) μm, ellipsoid, with a 1.5-2 μm broad and sometimes eccentric germ pore; cheilocystidia lageniform, often capitate; pleurocystidia lageniform to utriform. On soil mixed with wood chips.
Here’s is Peck’s protologe for Naucoria platysperma (Bull. Torrey bot. Club 25: 324. 1898)…Singer tranfered it to Agrocybe in 1973:
Pileus convex, becoming nearly plane, glabrous, slightly tinged with ochraceous or reddish-yellow when young, soon whitish, the margin at first adorned with vestiges of a white flocculent veil, flesh white ; lamellae moderately close, slightly rounded behind, pallid, becoming brownish ; stem equal, stuffed with a white pith, slightly flocculent or furfuraceous above when young, whitish, the mycelium sometimes forming white thread-like strands ; spores broadly elliptical, 15 µ long, 12.5 µ broad.
Pileus 2.5-3.5 cm. broad; stem 3.5-5 cm. long, 2-4 mm. thick.
On the ground, Compton, California. Professor A. J. McClatchie.
This species differs from N. pediades and N. semiorbicularis, to which it is related, by its larger broader spores and paler color.
It does look similar to Agrocybe pediades, but a bit chunkier than that species. I would expect A. pediades to grow in grass, not from the dirt.
my sense of mock outrage of having to lump these two collections together.
Heck, the two spore measurements didn’t even overlap; 11.0-12.4 X 7.4-8.6 microns vs 15.0-16.1 X 10.0-11.0 microns.
By the way, I did find a description of sorts for Naucoria platysperma in Charles McIlvaine’s old One Thousand American Fungi, in which he claims “This species differs from N. pediades…by its larger broader spores and paler color.” the spores in his descr. are “broadly elliptical, 15 microns long, 12.5 microns broad.” That’s even wider than my measurements but I assume he was approximating from Peck’s description and probably from one collection. He notes that the collection was from Compton, California.
So I guess I have that option or maybe just go to Agrocybe sp.
As far as becoming an Agrocybe specialist, I have to quote John McEnroe; “You can’t be serious!”
This might not be your problem… but if all you have to go on is those photos and those spores… it does look a lot like Agrocybe, so we should go with that. Although there is also Pholiotina as a possibility (not sure actually how people are really sure that one is not the other in all cases (maybe they use their gut…)).
But using the spores, it seems that in Agrocybe, there is the section Pediades, and this one you get by the fat spores. So you have that much info at least. That the spores should be over 7um in width, and have an apr. 2um wide germ pore. In this one, that is what you have, in the other one they are a little narrow, but are still about 7um wide.
But in the descr. that I have, which looks pretty good, when you look at the spore size, they site them as 11.5-18.5 × 7.5-12.0 um, with “ave.” values of 12.5-16 × 8.0-11.0 um (another source sites spores 10-16 × 7-11 um). Which is about as broad as I’ve seen for a citation of spore size. So if the spores are somewhere in the ball park, well that is good enough for this species it seems.
Other than that, I guess you have your gut on the species… but you need to site something other than just spore size for that to work. The problem really is that the spore range is just too large for the descr., so there isn’t much you can do with that. Without any other info, then you still get call these both A. pediades it seems…
Other problem seems to be with Agrocybe pediades var. platysperma, this seems to be sited no where except for Arora. I think this is a typo really, and he might have meant Agrocybe platysperma. Which I also can’t help you with, since I don’t seems to have a desc. of that one anywhere…
So, other than that, maybe they are different species, and maybe one is a new undescribed species? And if you want to show that, then welcome to my world, and get all the sources on Agrocybe that you can, and start collection more, and get a set of 10-15 collections, and start to show a consistent difference in the spore size along with some other observables. Compare to all known descr. (and go through the history of each to make sure they are still taxonomically valid). And maybe show a new species. I don’t think anyone has done much with Agrocybe is California, so it could be true… (no seriously I’m not joking, you should do this, it’d be cool!).
Or I think you’ll have to go with A. pediades…
Or… there is also A. putamininum with a spore size of 9.5-13.5 × 6.0-8.0 um, and a germ pore apr. 1.2 um wide. But this one should have a rather thick stipe, 5-8 mm wide perhaps…
So, do as you will with that info?
Unfortunately I didn’t save them so I won’t be able to elaborate on those points. However, I think even a diehard lumper would take notice of the spore size differentials.
Of course, I’m assuming you agree with the Id on the later observation.
Looking in the Flora Agaricina Neerlandica, at the Agrocybe monograph by Nauta, these look pretty good for just Agrocybe pediades var. pediades, if you go by what is given here. It looks like the important feature of the section Pediades, is the spores, and that they are more than 7 um wide, and the germ pore is close to 2 um wide. Which fits here. For Agrocybe pediades var. pediades he sites a spore size on “average” 12.5 – 16.0 × 8.0 – 11.0 um. Which seems to fit your measurement just fine (and seems to have a strange def. of average…).
He doesn’t seem to site any “var. platysperma”, but things seems to match well enough for “var. pediades”. Actually Index fungorum doesn’t list a “var. platysperma” either. There is an Agrocybe platysperma though… don’t know anything about that one.
So, I think you can go with Agrocybe pediades here just fine it seems.
Nice observation and images, the spores are very large.
Created: 2010-03-02 21:58:01 GMT (+0000)
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