Observation 47287: Amanita sect. Vaginatae sensu Zhu L. Yang
When: 2010-06-21
No herbarium specimen

Notes: White spore print. Gills aren’t quite as pink as the photo makes them seem.

[admin – Sat Aug 14 01:58:40 +0000 2010]: Changed location name from ‘Bloomington, Indiana’ to ‘Bloomington, Indiana, USA

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You might look at the following….
By: R. E. Tulloss (ret)
2010-06-24 05:43:07 CDT (-0400)

Here are some possible globose to subglobose spored species that could fit your observed material. Of course, there could be other possibilities as well…including undescribed species.

If you found the specimens near cottonwood or aspen (or other member of the genus Populus) you might consider A. populiphila, which is sometimes reported to have pinkish or orangish gill edges…but this should have shorter striations on the cap margin.

In the eastern states we can start seeing Amanita vaginata var. alba sensu auct. amer. (that is, the white species that is mistakenly called “A. vaginata var. alba” in U.S. field guides, etc.).

There is also a white or whitish species that has a very weak volval sac (breaks up into patches and leaves a strangulate (stretched) zone on the lower stem. I have given the latter the provisional name “Amanita cremeosorora” (cream sister) because of its morphological similarity to “A. sororcula” (little sister) and “A. borealisorora” (northern sister).

You put in a good effort on this observation.

Very best,

Rod

Spores
By: Kira (Kiradee)
2010-06-23 18:02:57 CDT (-0400)

So I was able to get a look at the spores, mostly from a scraping of the spore print I took. They seem to be globose to subglobose, though I didn’t have hours with a microscope to be absolutely positive, and they all measured from 9-10 μm from the apiculus to the other end. They also seemed to have a particularly defined and sizable apiculus – I’m not sure if that’s standard for an Amanita, or if that matters. I haven’t done a whole lot of microscopy before.

Looked at the gill as well, and was able to find intact basidia, but it wasn’t easy…the specimen is entirely dried now, so I could certainly give it another go if it might be worth it. What would I be looking for?

Thanks for your help…

Skirt
By: Kira (Kiradee)
2010-06-22 20:01:45 CDT (-0400)

There was no ring or skirt on the stem at all. I will be sure to let you know if I get some spore data. Thanks for telling me what to look for!

What you might look for…
By: R. E. Tulloss (ret)
2010-06-22 17:29:38 CDT (-0400)

I didn’t ask about a ring or skirt on the stem.

The pink gills may or may not be useful. If you find that the spore not globose when viewed from the side, then you might consider A. ristichii as a possibility. If often has pinkish looking gills. The spores will be very distinctly ellipsoid to elongate and rather chunky, large for the genus Amanita. An old cap is not very useful for looking at basidia and the structure of the gills…these tissues collapse and gelatinize rather quickly compared to other parts of the fruiting body. Try to measure at least ten spores positioned so that (1) you can eee the apiculus on the spore (the projection by which the spore is originally connected to the basidium) in focus, (2) you can see the flattened area adjacent to the apiculus (this means you are looking at the spore in side view, and (3) both ends of the spore are in good focus (the apiculus is near one end and the longest line parallel to the flattened area near the apiculus joins the two ends of a spore). If a spore is not globose or subglobose, it is much easier to find examples in side view than when the spore is globose to subglobose. Persistence is required (hours sometimes) to find spores in the correct position for measurement when the spores are globose.

If you find this entity again, make sure that it is starting to drop spores, and then dry it quickly to save the internal tissues of the gills. Then it will be much more valuable in terms of microscopy.

If you can get some spore data, I hope you will share it with us.

Very best,

Rod

Questions
By: Kira (Kiradee)
2010-06-22 16:54:58 CDT (-0400)

R.,

Unfortunately, I did not photograph the base of the stem – but – I remember that it did not have a clearly defined volva.

The cap is brownish now, but it’s also really old and dried up at this point, so I think that explains the color change…it was probably about 30-40mm across, and about the same in height. I do still have the spore print, and I also still have the cap. I am trying to get access to a scope at the nearby university – I can certainly check out spore size and shape and the like – is there anything in particular that would be good to look for?

Thanks for getting back to me!

Kira

Thanks for your note drawing my attention to this observation…
By: R. E. Tulloss (ret)
2010-06-21 22:48:33 CDT (-0400)

Hello, Kira.

I got your email. My first guess would be Amanita vaginata var. alba in the sense of U.S. authors, but there are other possibilities.

I understand your comment about the pink coloring of the gills in the photo. A lot of today’s digital cameras (at least on default settings) over emphasize the color red.

Did you get a photograph of the base of the stem of this critter? Did you find older species in which the cap had changed color? Or has the cap of the specimen you photographed changed color since you collected it? What was the approximate size of the cap? Did you keep the spore print? Do you have a access to a scope in order to look at the spores?

R.

Created: 2010-06-21 18:42:17 CDT (-0400)
Last modified: 2012-06-06 17:39:21 CDT (-0400)
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