Observation 194665: Amanita magniverrucata Thiers & Ammirati
When: 2014-12-04
No herbarium specimen
0 Sequences

Proposed Names

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
I received an email question asking for further clarifications. EDITED
By: R. E. Tulloss (ret)
2014-12-26 12:12:47 CST (-0500)

I have now rewritten my original comment (below) in an effort to make it clearer.

Debbie asked an additional question: What is the composition of the smooth surface between warts when the cracks in the volva do not descend into the cap flesh?

There are several possibilities. Here are three.

(1) A smooth surface between warts could be part of the volva that didn’t split into warts. This might have been the case in a specimen examined by Ammirati and Thiers in the original description of magniverrucata because they interpreted wart tissue as pileipellis. [You could imagine a mechanism in which the radial to interwoven structure of layers to which the universal veil is attached resist splitting and remain covered by a thin layer of universal veil which is stretched relatively smooth.]

(2) The smooth surface between warts could be a part of the transitional zone between warts and flesh. I haven’t seen this; however, without a better knowledge of the mechanics of cap expansion in magniverrucata, there’s no saying it can’t happen.

(3) The smooth surface between warts could be a part of the flesh of the cap. I haven’t seen this either.

I would be glad to look at material that seems to be magniverrucata with a smooth surface between warts and report what is going on. There is no herbarium specimen corresponding to the present observation according to MO. So some material from some other well-documented observation of a specimen with a smooth, unbroken surface between warts would be of use.

Very best,


In several recent posts about A. magniverrucata, … EDITED TWICE
By: R. E. Tulloss (ret)
2014-12-25 19:13:27 CST (-0500)

there are typos that are at cross purposes with each other. This is, unintentionally, muddying the story of the unique anatomy of A. magniverrucata.

There are a number of amanitas that do not have a well-formed pileipellis (cap skin) layer. In these species, the universal veil transitions through an intermediate layer (that may be very thin in one species and thicker in another) into the flesh (context) of the cap.

A pileipellis in the genus Amanita comprises hyphae with subradially organized or less organized orientation, but always running parallel to the apparent surface of the cap. This orientation of the hyphae composing the pileipellis is called periclinal… (it is “inclined to follow a perimeter” to speak metaphorically).

Among the amanitas that lack a distinctly bounded and well-organized pileipellis are (1) most of the non-mycorrhizal species, (2) the southeastern North American species A. rhoadsii, and (3) A. magniverrucata.

The apparent warts of A. magniverrucata are composed of either (a) universal veil alone (in this case the warts can be large) or (b) both the universal veil and the flesh of cap. In both cases, the warts are pyramidal. If the warts appear to be more than a quarter inch high, it can be suspected that only the upper part of the wart is universal veil while the lower part of the wart is cap context (flesh).

To know the anatomical situation with greater certainty, it is necessary to use a microscope. One makes a very thin slice vertically through the wart-like pyramid of tissue(s). In the upper part of the pyramid, if you have a good section, you will see that the tissue has a strong vertical orientation to its elements or you could say that the hyphae and rows of cells are dominantly organized perpendicular to the expanding/flattening curve of the cap. This orientation is called anticlinal (…it does the opposite of paralleling a perimeter, to speak metophorically again). This is in strong contrast to the orientation of the large inflated cells of the cap flesh, which are roughly radially oriented or disorderd and the hyphae of the cap flesh which form a very open matrix in which the inflated cells are found.

In other words by examining a pyramid on the cap of magniverrucata you will see it is made of universal veil alone (anticlinally oriented tissue) or is composed of multiple layers with the anticlinally oriented tissues having a transitional zone below them and, below that, the flesh of the cap.

I described this in a paper honoring the 40th anniversary of Dr. Bas’ thesis. A link to that paper can be found in the “citations” data field at the bottom of the techtab on this page:


Since the issue of DNA has arisen, it should be said that the DNA sequences supposedly representing magniverrucata in the fine research of Ben Wolfe represent, instead, a species of section Amanita. I am in the process of correcting this matter.


Rod Tulloss

altho the cap skin can smooth with age and environment …
By: Debbie Viess (amanitarita)
2014-12-25 17:50:44 CST (-0500)

the warts still arise from the cap tissue, not the veil. If you pull them off, they leave a divot behind, not a smooth skin. you can see this in your photo where some warts have been removed.

Created: 2014-12-25 12:34:07 CST (-0500)
Last modified: 2014-12-25 12:39:05 CST (-0500)
Viewed: 100 times, last viewed: 2017-06-19 17:20:24 CDT (-0400)
Show Log