The spores of Amanita nothofagi are reported to be
(6.5-) 7.5 – 9 (-13) × (6.5-) 7.5 – 9 (-13) μm; avg. Q = 1.05 (globose to subglobose); and the spores of A. karea are reported to be
6.5 – 9 × 5.5 – 6.5 (-8) μm; avg. Q = 1.32 (broadly ellipsoid to ellipsoid).
The match is not perfect in either case; however, remember that ellipsoid spores will look globose if viewed from either end.

I get that the uppermost spore (in its improper orientation) is about 7.5 × 6.9 μm. With Q about 1.09 (hence, subglobose).

Also, if you measured the dark outlines in the spores, those are the outlines of the central guttule of the spores. The walls of the spores are very faint. Spores should always be measured in lateral view with the two end and the apiculus (little knob) all simultaneously in focus. Very hard to do for globose spores, but it can be done.

R.

Now that I make another measurement the spores are closer to 6×5.5µm.
In Geoff’s description he says A. karea can occasionally have globose spores, the size of the umber cells of the universal veil remnants could be a match for this species also, I would like to wait and see what he has to say about this observation!

Image 67422 shows globose spores that are about 5×5.5µm but they could be slightly immature because they were obtained from the lamellae surface not a print!
Image 67423 shows a basidium with very immature spores.
Scale divisions in all my micrographs are 2.5µm regardless of how magnified the image is, so the best way to measure the cells is to measure them with a ruler then transfer that measurement to the scale.
I hope that makes sense!

In image 67422, it says the divisions are 2.5 microns and the spores seem to be globose and about two divisions in diameter, which would make them 5 microns wide.

In 67423, the basidium in the middle has sterigmata that end in balls, presumably spores, that are about 2/3 of a division wide. The text says the divisions are again 2.5 microns.

Are those spores actually 1/3 the size of the others (due to being immature, perhaps) or is it maybe the case that 67422’s magnification actually makes the divisions 1 micron rather than 2.5 (1000x instead of 400x, probably, in that instance) and the text got it wrong?