Observation 5869: Cystoderma fallax A.H. Sm. & Singer

When: 2007-12-31

Collection location: Los Trancos Preserve, Palo Alto, California, USA [Click for map]

Who: Douglas Smith (douglas)

Specimen available

Going back over some Cystoderma collections, to see what can be seen… putting these under the scope.

The first micro-shot is of the cap surface in radial section at 400x in Meltzer’s. Here the epithelium of the surface can be seen, with the pigmented globose cells. There don’t appear to be any arthospores in the pileus context, but I not sure what I should be looking for there, but in C. fallax you are not supposed to see hardly any.

The second micro-shot is of the gill edge at 400x in Meltzer’s. What is important here is what you don’t see, there are no cystidia. Also the spores can be seen to be amyloid.

The third micro-shot is of spores from the veil tissue at 1000x in Meltzer’s. The spores are ellipsoid to subglobose and amyloid. There are lots of spores to get the size well, so the ave. size was found to be : length – 4.73 +/- 0.30 (err 0.07) um, width – 3.59 +/- 0.24 (err: 0.06) um – q : 1.32 +/- 0.08, on 28 spores.

So, this pretty much agrees with the pub. description for C. fallax. Except for the width of the spores. The length of the spores is a little long 4.73 +/- 0.30 compared to 4.44 +/- 0.24, but those are consistant. The width was found here to be 3.59 +/- 0.24, compared to 3.05 +/- 0.12 that was pub., which aren’t really consistent. This makes me wonder a bit if I choose a little large in the measurements of size, and that small error shows up in determinations of very short distances like this… Anyway, it is close enough given everything else.

So, this one is a good obs. of C. fallax for California. The main feature it seems for C. fallax is the veil, where it is a flaring, persistent, membranous veil. There are a number of obs. that are labeled as C. fallax here, that I don’t think they are. There is also a note in the study that C. fallax is rusty brown, and never yellow-ocher. I think a number of C. fallax obs. here, esp. from Mendocino area, are not, but some other Cystoderma species.

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Created: 2008-01-04 01:54:20 CET (+0100)
Last modified: 2008-01-04 01:54:20 CET (+0100)
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