Observation 66963: Amanita sect. Vaginatae sensu Zhu L. Yang

When: 2011-05-05

Collection location: Saleeby-Fischer YMCA, Rockwell, North Carolina, USA [Click for map]

Who: Matt Sherman (Shermanii)

Specimen available

Growing from soil at the base of a Pinus virginiana in mixed, predominantly pine forest.

3.3cm broad, convex with umbo, gray to “silvery”, striate margin ( .7cm), a large patch of white tissue covers the majority of the cap

Free, Close, White to Creamy

8cm long, .5-.7cm wide, gradually enlarging from apex to base

Universal veil remnants:
On cap as large patch of white tissue
Soft tissue connected to base of stipe

I couldn’t put a name on the smell, but it was not pleasant and smelled “disagreeable”


Globose, smooth


Basidium 1000x (1.15μm per division) in Lactophenol Cotton Blue
Basidium 1000x (1.15μm per division) in Lactophenol Cotton Blue
Spores 1000x in Melzer’s Reagent

Proposed Names

-60% (2)
Recognized by sight

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Spore Sizes
By: Matt Sherman (Shermanii)
2011-05-13 17:05:44 PDT (-0700)

globose to sub-globose, smooth, inamyloid

Length x Width
11.5 × 10.35
10.64 × 10.35
11.5 × 11.5
11.5 × 11.5
12.65 × 11.5
12.1 × 11.5
11.79 × 10.93
10.35 × 10.35
11.5 × 10.35
11.5 × 11.5

12.1 × 11.5
11.5 × 10.35
10.35 × 9.8
11.5 × 10.93
10.93 × 10.93
11.5 × 10.93
12.1 × 11.5
10.93 × 10.35
11.5 × 10.35
11.79 × 11.5

11.46 × 10.89μm
L , W
12.65μm, 11.5μm

10.35μm, 9.8μm

Here’s a species to check out…
By: R. E. Tulloss (ret)
2011-05-06 06:51:37 PDT (-0700)

You might want to compare your material with the information on the “technical” tab on this page:


I have no notes indicating whether either of the collections assigned to sp-V01 had cap margins that were tuberculate-striate. Otherwise, the match is not too bad. And note (for what it’s worth) that this entity was first found in Virginia.

Very best,


Good question….
By: R. E. Tulloss (ret)
2011-05-06 06:28:20 PDT (-0700)

With regard to including the apiculus in the measurement of spores, the answer is “no.” Consider that the apiculus is a projection from the spore, and when we talk about the shape of the spore we are talking about the shape excluding the apiculus. Hence, if length/width is to be a quantitative way of talking about shape, the length and the width going into the computation of the ratio have to be the length and the width of the spore ignoring the apiculus. Some people don’t realize this and they have published, lengths, widths, and length:width ratios that don’t match those of the researchers on Amanita in the last 60 years (e.g., Drs. C. Bas and Z. L. Yang). It may go without saying, but I’ll say it anyway: When you have a spore in lateral view, measure length parallel to the flattened area adjacent to the apiculus and the width perpendicular to the length. Sometimes the “flattened area” may not be strongly flattened, then the length is largest measurement across the spore and the width is the measurement perpendicular to the length. The value of Q can never be less that 1.0 in order to be meaningful. If you ever find a spore for which the width appears to you to be greater than the length, consider carefully if your perception of which dimension is length (width) holds up to second thoughts. If the answer is, “yes, it does,” then forget about measuring the spore, which can be considered abnormal. Introduction of a length:width ratio of less than 1.0 into your computation of the average of that ratio will depress the value of the average and alter the resulting quantitative “shape” information. Think about this: If a length:width ratio of 1.0 means that spore is perfectly spherical (see the table of quantitative/qualitative shapes descriptions below), then what in heck is 0.85? The answer is that it’s meaningless.

If you had decided that length and width were reversed when you first considered the spore in question (several sentences ago), then you woul have gotten a length:width ratio of 1/0.85 (in our example). Perfectly cool, and meaningful according to Bas’ table. It was the decision that the “width” in some sense and for some reason was larger than the “length” that made the data with regard to that individual spore incompatible with “further processing.”

Sadly there are some large works that have been published in recent years that are spoiled in part because the authors did not realize that a length:width ratio less than 1.0 does not serve the purpose for which the ratio was developed for taxonomic use…namely, the quantifying of the concepts of shape.

In MYCOTAXON volume 115, there will be a book review by me of such a work. If I remember correctly, every single set of spore data on every species is spoiled by the length:width ratio (Q) “less than 1.0” problem. Considering the effort put into collecting and revising of the material and into the writing of the paper, I think it very sad that results are pretty much useless to other workers concerned with taxonomy of the Amanita family.

If you contact me through MO’s email feature, I will send directly to you th booklet that Cristina Rodriguez Caycedo and I have used to teach an introductory seminar on taxonomy of the Amanitaceae. I hope it will be useful to you.

Very best,


By: Matt Sherman (Shermanii)
2011-05-05 22:20:28 PDT (-0700)

Thank you very much for checking into my observation.

I do not know the color when the cap was moist, but the specimen is still the same color now, as it was when I plucked it from the ground (if that is of any use).

I have an average for the spores but upon reading that the apiculus needs to be visible to correctly measure the spore, I decided that I need to measure 20 more spores the correct way, then post my results.

When measuring spores, should the apiculus be included as part of the length or width of the spore?

Of course, all the options are unpublished taxa…
By: R. E. Tulloss (ret)
2011-05-05 17:51:08 PDT (-0700)

My cheat sheet is organized by average length/width, average length, a very basic description of cap color, and some other stuff that’s not relevant in this case. After picking the set of best matches (none of which had perfectly globose spores), I then checked all the macroscopic data that was avaiable for the items that came up.

Here’s what I got: There were three taxa listed as having tuberculate-striate margins: species N28, species W13, and “vaginata sensu Dav. T. Jenkins” and one for which there is no data easily available at the moment concerning whether the margin is tuberculate or not. I eliminated one of the first group (species N28) on the grounds that its spores were just too much smaller than the ones that you report.

I would guess that your average length is going to come in around 11.0 μm or just a bit larger. This characteristic eliminates none of the remaining three taxa. I suspect that you and I don’t have the same methods for spore measurement, and that this is the reason that your spores seem so much rounder than I would expect. Because there is a flattened area adjacent to the apiculus, when spores are viewed in strictly lateral view, they only rather infrequently have width equal to length.

My mentor, Dr. Bas, began to use the length divided by the width as a numerical replacement for qualitative terms (like globose, ellipsoid, etc.) in the 1960s and created a table to standardize the qualitative terms…defining them by ranges of the ratio of length to width: 1.0 – 1.05 was “globose”; 1.05 – 1.15 was “subglobose”; 1.15 – 1.30 was "broadly ellipsoid; 1.30 – 1.60 was “ellipsoid”; 1.60 – 2.0 was elongate; 2.0 – 3.0 was “cylindric”; and greater than or equal to 3.0 was “bacilliform.”

Over the last 33 (going on 34) years I’ve found this ratio very useful in Amanita taxonomy (not by any means a solution to all the many taxonomic problems, but very useful).

To be very honest with you, measuring nearly round spores can be a very big pain. It can take me very long times to come up with 20 measurements…hours. I persist because the results really help in separating species (not always, but a lot of the time).

In order for me to measure a spore, I have to see the apiculus clearly. It can’t be in a “terminal” position (because this means I’m probably looking the top (flattened side) or the apex of the spore. If a spores is symmetrical with respect to the center-line of the apiculus, you are seeing the spores from the top or from the apex; and not from a lateral view. If you can’t see the apiculus at all, you are looking at a spore rotated in such a way that you’re seeing the end opposite the apex of the bottom or a bit of each.

With nearly round spores, the chance of getting a good lateral view in a mount of spores is fairly small. You just have to wait until the odds are on your side…then wait until the odds are on your side…then wait until…etc.

Another caveat. The number of species of sect. Vaginatae in eastern N. America is large…probably larger than my experience would indicate. They often occur singly; and, for the most part, they occur very irregularly.

With all that said, I’m inclined to think that the best I could do for this specimen (given the pictures and available data) is to say that it’s a pretty good match to what is known about “A. vaginata sensu Dav. T. Jenkins”; and what is known is not enough to be joyful about.


Thanks, Matt.
By: R. E. Tulloss (ret)
2011-05-05 17:05:54 PDT (-0700)

I’d like to add also that I think the ridges between the cap’s marginal striations are tuberculate. Do you have any indication of whether the color was a gray when the cap was moist as it is after some in situ drying in your pictures?

I don’t know of very many always gray (from fresh to dry) species of sect. Vaginatae in eastern N. America with globose or subglobose spores. So I was just checking my Vaginatae cheat sheet when I noticed your additional info. I’ll check for things with nearly globose spores, gray caps, and spore length in the range of 10.4 to 12.6 um. Did you compute an average length?

I think you meant to say that the stem is narrowing upward rather than expanding. No biggy.

Back in a couple of minutes.

Rod Tulloss

Spore sizes
By: Matt Sherman (Shermanii)
2011-05-05 14:55:33 PDT (-0700)

Smooth, Globose, Inamyloid
20 spores were measured.

Length x Width
10.12-12.65μm x 10.35-12.65μm

Created: 2011-05-05 14:11:47 PDT (-0700)
Last modified: 2011-05-25 08:58:23 PDT (-0700)
Viewed: 139 times, last viewed: 2017-08-15 16:17:17 PDT (-0700)
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