Missing basidia

[BROCSMAN]

I'm still trying to get the hang of using a microscope. I'm pretty sure this is Panaeolini foenisecii. Ths spores look right, and seem about the right size. I think these are the cheilocystidia, and they look fine too. But I can't find any sign of the basidia. I must be doing something wrong. Can someone point me in the right direction please.

I'm afraid this is about the best my scope camera will do.

[Chris Yeates]

I think I'm correct in saying that P. foenisecii has a sterile gill edge; that means there will be no basidia along the edge, and as this species does not have pleurocystidia (i.e. cystidia on the gill surface) I must be looking at the gill edge . . . . therefore you won't see basidia

so you're not doing anthing wrong! don't worry; frankly if your fungus has rough basidiospores and the general appearance and habitat are OK, then I'm sure you've got your ID right

in the first instance I would recommend getting to grips with checking whether basidia are two-spored or four spored; to do this take a piece of gill and place it on a dry slide; then using a relatively low power objective (so you don't mess up the lens) gently focus down and you will soon get the knack of spotting the characteristic pattern of four (as on dice) or, less frequently pairs of spores (to get the latter simply use the Agaricus bisporus shop mushroom)

later on practise in water mounts with small pieces of gill - generally the smaller the better - and try staining in Congo Red, because you sometimes need to be able to see whether the basidia have basal clamps etc.

if all this is already familiar to you I apologise - though it may be useful to others

keep at it

best wishes

Chris

[BROCSMAN]

It's not familiar at all, and it is exactly the sort of advice I was hoping for.

Many thanks Chris. I'll keep practising!

[SheffieldLass]

Originally Posted by BROCSMAN

I'm still trying to get the hang of using a microscope. I'm pretty sure this is Panaeolini foenisecii. Ths spores look right, and seem about the right size. I think these are the cheilocystidia, and they look fine too. But I can't find any sign of the basidia. I must be doing something wrong. Can someone point me in the right direction please.

I'm afraid this is about the best my scope camera will do.

You are doing fine.

You did right to look at the gill piece initially without squidging the coverslip too hard on it, as the structure of the gill edge and cheilocystidia are clear (and pleurocystidia in species with them can often be seen within the gill body).

Once you've seen the structure, then squash it a bit more (it will get more jumbled up, and cheilocystidia and pleurocystida can get mixed together). If you haven't already seen the basidia properly with the initial squash then by doing this you'll probably get a much clearer view of them as they separate out and also you will probably separate out some cheilocystidia from the gill edge to see their full shape and length, rather than just their tips. It makes it much easier to measure those that need checking. In some fungi (like Coprinellus/Coprinopsis) the cells seem to disintegrate with over enthusiastic pressing though, so you need a light touch on those.

If it had been a fungus with pleurocystidia, by doing first a gentle press that retains the structure you may have seen them within the gill body, and be able to differentiate them from the gill edge cheilocystidia. Another check for pleurocystidia is to take a gill then trim off all the edges so that you have an internal bit of the gill, so there won't be a gill edge and cheilocystidia to confuse you! So if you see any specialised cells there, they will be pleurocystidia. If you don't, then they probably don't have any. This is particularly useful if the cheilocystidia and pleurocystidia are rather similar, and if part of the id is to establish whether that particular species has or doesn't have pleurocystidia.

I found it good to practice first on species that I was fairly confident of their identities, because I could check in the books (or Bioimages) what I should be looking for and then search for it, and by that method get to know what it was that I was looking at, what the cells actually were.

Cheers
Melanie

[Chris Yeates]

good advice

another way to see gill surface cystidia (pleurocystidia) is to (from top down) cut as thin a section as you can (safety razor blade, or normal razor blade with other end taped off with masking tape or similar) making two parallel cuts and then looking first at low mag. in air and then proceeding through the liquid mount stages

I'm thinking of ways to put two razor blades spaced a little apart to cut such sections - of course with a freezing microtome and all the gubbins this would be unnecessary . . . .

Chris

[BROCSMAN]

Well, I've finally got some fresh material, so I'll give it another try this weekend. (Football permitting!).

Thanks all.