Psathyrella for ID Assistance

[RobSutton]

Found this rather nice specimen at the base of a beech tree on limestone at Malham Tarn - on Tuesday 13th October 2009, cap up to 30mm, stem c4mm diameter:



Under the microscope it had rather small spores (L 6.3-7.5µ W 4.1-4.8µ Q 1.5-1.9) with no obvious germ pore:



Cheiliocystidia with crystals:





A few pleurocystidia:



and what seems to be a persistent veil made up of globular cells covering the whole of the cap:



I thought it was one of the paler Psathyrella species but when trying to key it out in Funga Nordica I can't seem to get anything that agrees with all of it's characteristics. There don't seem to be many with this type of veil (if I'm interpreting the micrograph correctly) but the spore size is too small for any that I get to using their keys (eg P.globosivelata) and are not in the Checklist of the British & Irish Basidiomycota anyway.

Any help, suggestions or nudges in the right direction much appreciated as always.

[SheffieldLass]

Hi Rob
I've had real trouble with Psathyrella too ... I'll take a look at your pics when I've got a bit more time and compare with mine, but as I've not managed to id mine don't hold your breath for a name! I never seem to be able to pick out the veil cells, and that seems quite important to enable reaching an id. The globose cells on yours are most probably the cellular cap cuticle ... it took me a while to realise that on mine at any rate, I thought they were veil cells for some time. See where you get to with the key by assuming the other type of veil.

Melanie

[ManwithNoname]

A few thoughts which may help, Rob.

First of all, I can't see any evidence of a universal veil on the cap. Second, I think your spores do have a germ pore, although not as distinct as for some species. Several of them have a paler round spot at the appropriate end of the spore. For example, look at the spore to the south-west of the number 7 on your graticule, and the one directly above it.

Using the key in the old Nordic Macromycetes takes you to Psathyrella cernua. See what you think.

'Cap drying to white, sordid white or sordid pale grey. Sp with germ pore. Cap 1-4.5 cm, paraboloid, then convex, sordid brown or greyish brown; veil absent. Stem 1.5-4 cm x 0.2-0.9 cm, cylindric, white or whitish, apex pruinose. Sp 6.5-7 x 4.5-5 microns; pleurocystidia utriform or ventricose or subcylindric, rather thin-walled, muricate; cheilocystidia similar, intermixed with a few, small, sphaeropedunculate elements - On stumps of deciduous trees.'

The Checklist says:
'Habitat: On decayed wood of deciduous trees, usually Fagus in mixed deciduous woodland.'

'Notes: Rare'

[RobSutton]

Thanks for the guidance - it does seem to key out relatively straightforwardly once I get the veil business sorted out. I think I was misled by the tattered area on part of the cap of the main specimen and the fibrous material on the stems and then when I saw that easily detached layer of globular cells I put two and two together to make seven

All part of the learning experience and I'm sure there will be other misinterpretations I'll be making as I go along that will need correcting. Being able to access other peoples experiences is proving invaluable to me so thanks particularly here to Melanie and Mr. manwithnoname but also to all who contribute here.