Blackening dermoloma

[SheffieldLass]

Does anyone know the spore sizes of Dermoloma magicum? I have a Dermoloma which has amyloid spores (6.1) 6.7-8.0 (8.7) x (3.5) 3.8-4.7 (5.4)um. It also has a tendency to blacken, on the cap and along the gill edge. Given the amyloid spores of this size it could be D pseudocuneifolium, but as I don't know what size D magicum are don't know if this might also be a possibility. I'll post pics later. Only took one in the field as I'd run short of memory ... but could do with some, particularlyof the blackening, and have lost the daylight now ....

Melanie

[Chris Yeates]

hi Melanie

from the original description in PERSOONIA — Vol. 17, Part 4, 2001:

Pileus 25-50 mm wide, conico-convex, convex or plano-convex, with or without obtuse umbo, finally sometimes with the centre depressed, not hygrophanous, brownish grey to rather dark grey-brown (K. & W. 6C3,6C4,6E5,6F6); margin even or lacerate, not striate; surface dull, smooth to slightly squamulose near centre, even or radially wrinkled to rugulose, sometimes cracked, exposing white context beneath.

Lamellae (L = 28-40,1 - 1-5) adnate to emarginate, moderately crowded to subdistant, rather thick, interveined, ventricose, up to 8 mm broad, pale grey to grey-brown (K. & W. 5C4,6D3).

Stipe 30-65 x 4-12 mm, cylindrical or slightly tapering downwards, narrowly fistulose, pale grey to beige, base some-times ochre-yellow, fibrillose striate lengthwise, in addition minutely floccose, in some specimens (Arnolds 6701) with grey flocks. Context firm, compact, whitish, when cut soon discolouring orange-red, then black in places, in particular in base of stipe and above lamellae.

Smell farinaceous to herbaceous. Al l parts of basidiocarp quickly turning orange to red when bruised, after a while (15-30 minutes) blackening. Colour of spore-print unknown.

Spores 6.0-9.0 x (3.5-)4.0-5.0(-5.5) um, on average 6.7-7.8 x 4.4-4.5 um, Q = 1.35-2.0(-2.3), av. Q= 1.50-1.75, ellipsoid to ellipsoid-oblong with prominent hilar appendix, often with one or two droplets, amyloid.

Basidia 26-38 x 6.5-7.5 um, clavate, 4-spored or mixed 4-, 2- and 1-spored, in exsiccata with brown content.

Lamella-edge fertile. Hymenophoral trama subregular, made up of cylindrical to inflated elements, 35-85 x 5-16 um. Pileipellis a unistratous hymeniderm, made up of erect, branched hyphae with swollen, ovate, clavate to spheropedunculate cells, 17-52 x 7-22(-35) um), often slightly thickwalled, with parietal to encrusted brown pigment; sometimes with scattered, subcylindrical pileocystidia, 52-58 x 6-6.5 um. Stipitipellis a cutis of repent hyphae, 3-8 um wide, with pale yellowish parietal pigment, in addition sometimes minutely encrusted, producing dense clusters of caulocystidia, in particular near apex of stipe. Caulocystidia subcylindrical to clavate, 23-47 x 4-14 um, thin-walled, hyaline.

Habitat — Terrestrial, saprotrophic, solitary or in small groups in old, not or weakly fertilised pastures on dry, loamy, often calcareous soil. Aug.-Oct.

how's that ? . . . . pure magicum

also check out PM in ten minutes or so . . . .

best

Chris

[SheffieldLass]

Thanks for your speedy reply Chris. Now I need to read it ... and copy it for future reference .... I suspect it is D pseudocuneifolium rather than D magicum as it doesn't redden before blackening, and the blackening is half-hearted, though actually with a distinct edge and fairly convincing on the cap of two ... hmmmm ... better check all the other details ...

Melanie

[Chris Yeates]

Originally Posted by SheffieldLass

Thanks for your speedy reply Chris. Now I need to read it ... and copy it for future reference .... I suspect it is D pseudocuneifolium rather than D magicum as it doesn't redden before blackening, and the blackening is half-hearted, though actually with a distinct edge and fairly convincing on the cap of two ... hmmmm ... better check all the other details ...

Melanie

just emailed you . . .

C

[SheffieldLass]

Well this is the only photo taken in the field of one group.



Not obviously blackening, except for the top of the one that is turned over, which you can't see, yet .... Stem bruising a bit reddish from handling.

Sorry about the quality or rather lack of it in the remainder, taken indoors under artificial light.


Top of the one that was turned over in the above photo. Some D cuneifolium I've found weather rather like this though. So at this stage wasn't thinking of Blackening Dermoloma.

It was only when I spotted this one that I began to wonder.

which has a very distinct type of blackening. However the gills of this one and stem show no obvious blackening:


One I cut today, which was bottom left in the field picture .. stem at base did redden a bit and then about 30 mins later was looking rather blackish, although it was drying at the same time, which might be why.

P.S. Just looked at these now, and the centre of the cap has turned very distinctly black with a very clearly demarcated edge .... so I'm becoming convinced these are D magicum.

Gills of the one bottom right in the field picture. With a black edge.


Spores in Melzers, turning bluish, which points to D pseudocuneifolium or D magicum , and size of spores (see 1st post) fits both:


Size of the caps were mainly 50mm dia. Which is supposedly too big for D pseudocuneifolium.

These are definitely Dermoloma by the cap structure, 40x:

Cap cell sizes 12-26 dia x 31-80um long.

Gill trama 10x:

Trama cells 6-23 dia x 31-70um long.

Caulocystidia:

6-8 dia head x 35-52um long.

Basidia 4 spored, 6-8.6 x 29-39um.

Now I've reached the end of the post, and having seen how the cap of the cut one has got a big black patch I'm pretty much convinced they are D magicum. At the beginning of this post I wasn't sure. Just shows what bruising followed by 30 minutes can do ....



Melanie

[ManwithNoname]

In case it's of any help, Melanie, I have posted below a photo sent to me by a friend of some specimens she collected from her lawn in August this year.



The distinctive colour changes reminded me of a couple of articles in Field Mycology and I was able to point her in the direction of Dermoloma magicum. It may help in comparing the nature of the "reddening" and blackening for this species. The initial colour change is actually more orange-brown than red, and appears similar to the bruising on the stem of your specimen.

[SheffieldLass]

Originally Posted by ManwithNoname

In case it's of any help, Melanie, I have posted below a photo sent to me by a friend of some specimens she collected from her lawn in August this year.



The distinctive colour changes reminded me of a couple of articles in Field Mycology and I was able to point her in the direction of Dermoloma magicum. It may help in comparing the nature of the "reddening" and blackening for this species. The initial colour change is actually more orange-brown than red, and appears similar to the bruising on the stem of your specimen.

Thanks Incognitor. The ones of mine don't seem to redden (orange brown) to the obvious extent of those in your photo, (but there is a reddish brown margin to the black) though these are getting on a bit, having sat a few days in the fridge waiting examination. But maybe my eyes are not tuned into the reddening ... I'd not noticed in the field how the stem of that one had reddened, and only noticed it on the photo later .

I've got some better photos today of them taken in daylight, (but on my lawn, not their original habitat).



And having decided that the photos are ok, just went to get them from the fridge to put them out to dry and noticed that since handling them new black patches have quite suddenly appeared. Something seems to trigger the blackening, but I don't think it is merely handling as these would be black all over by now . And they do it when I'm not looking .... they are now drying right in front of my nose, so I'll try to catch them at it ....

Melanie

[SheffieldLass]

Interestingly a friend found Dermoloma magicum yesterday out at Kedleston Hall. A first for her too. So conditions must be right for them just now.

[SheffieldLass]

Well, we found another group of Blackening Dermoloma on Monday, just a couple of fields away from the ones shown above.

The reddening on the stem was apparent even before they were handled, but became more obvious when picked. The blackening didn't happen immediately but one had developed black patches an hour or so later on the cap and stem, and the other had got blackening on the cap and stem by the evening.


some reddening at the base even before picking


More obvious reddening after picking


What they looked like by the evening.

I'm now convinced by the pattern of discolouring of these that they are the real deal .....

Anyway, now seems to be a good time to look for them .... happy hunting ...

Melanie

[mollisia]

Dear Melanie,

I'm just preparing a publication about Dermoloma magicum for a german journal, as we have found that species here in Germany 4 times now in the last years. Therefore I would be interestend in its overall distribution and want to ask you, whether you could specify the locations you made and that of your friend (location, date).

thank you very much and best regards,
Andreas