Collection location: Parque de Monsanto, Lisboa, Portugal [Click for map]
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I’ve known professionals who get by with 500×. If it has good quality resolution, it’s probably better than mine even at 1000x!
However, I highly recommend investing in a dissecting scope. It is one of my most prized possessions. Useful for so many things, even beyond lichenology and botany. Quality is less critical, so even the cheap one I bought on Ebay has performed admirably:
I have no dissecting microscope, so I have to do it with a head magnifier. Also I don’t have a personal microscope, but sporadically I can use one with the maximum of magnification 500×. I hope it be enough. As a matter of fact, first I have to find the specimen again.
Ideally you could place a few vertical slices of the apothecia under a microscope. Best way seems to be to place a specimen under a dissecting microscope, carefully slice one of the apothecia with a very sharp razor, trying to make the slices as thin as possible. There are various tricks involving thumbnails and other spacers, but it can also be done simply with a steady hand. My method is to make one cut near the left side, say, and clear away the edge on that side. Then make a few vertical cuts as thin as possible on that side. Cut them free from the substrate with a horizontal cut (very carefully so they don’t go flying off!) Place a drop of water on a slide, dab the edge of the razor in the drop, then touch the razor to the tiny slices. The water should cause them to stick to the razor’s edge. Now dab the razor back in the drop of water and it should release the slices. Now place a cover slip over them, squash gently if desired, and place under microscope. You will need at least 400x to see spores, better yet 1000×. It can be difficult to tell whether you’re just looking at a young ascus with rough-textured contents, or a mature ascus filled with hundreds of tiny 2 µm spores, especially at 400×. But if it’s Aspicilia or Ionaspis you should be able to see the mature spores pretty well even at 400×. If Acarospora, check for an ascus that has burst open spilling the tiny spores into the water surrounding it.
I suppose that the first step is to look at the asci and spores. How to make such preparation? If “dozens to hundreds” of tiny spores per ascus confirms, how to proceed?
Created: 2010-07-04 18:41:19 BST (+0100)
Last modified: 2010-08-14 19:38:43 BST (+0100)
Viewed: 55 times, last viewed: 2018-04-26 03:29:34 BST (+0100)