Ok, getting back to this question. I looked through the descriptions for S. caerulescens and S. ponderosus, and it turns out the clear difference to look for is that S. caerulescens has an ixotrichoderm, and S. ponderosus has radially aligned interwoven hyphae in a gelatin matrix. Also the descriptions state that both stain in the base wehn cut (and only the base), but S. caerulescens is blue, and S. ponderosus stains green (green? only green staining boletales I’ve heard of, and this isn’t a St. Patrick’s joke…). It would be good to see obs. of S. ponderosus and this, the next time someone sees one.

But anyway, I added a photo here of the ’shroom cut open, and bruised from the base to the cap with a knife edge. Only the base bruises blue, and a nice bright blue.

The micro-shot is of the cap surface in radial section in water at 400×. And here you can see the cells aligned pointed up to the surface, in a gelatin matrix, so this is your ixotrichoderm.

So, ok these are confirmed as S. caerulescens. Now it would be good to compare the same with S. ponderosus.

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Recognized by sight: The specimen on the right of the first picture sure looks like it has a white veil indicating S. caerulescens rather than S. ponderosus.

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By: Joshua Birkebak (Shua)
2008-02-19 08:11:46 EET (+0200)

When I look at the specimens they look to have a viscid veil… but It is hard to say with out actually having seen it!