Observation 64714: Amanita roseolamellata A.E. Wood

Proposed Names

0% (2)
Recognized by sight: Lucy sent me another photo that shows an annulus collapsed on the stem.
18% (2)
Used references: Compared to UNSW 84/305 which was illustrated by Wood accompanying his description of Amanita egregia D. A. Reid. See site listed below.
Based on microscopic features: See http://www.amanitaceae.org/...
82% (1)
Based on chemical features: “proposed fungal barcode” sequence matches (100%) that from roseolamellata from Lucy’s site.

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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The main influence on spore size/shape in your early collections, Lucy, was…
By: R. E. Tulloss (ret)
2015-05-05 23:04:01 AST (-0400)

that you tended to pick immature specimens and sometimes dried them before they really got into the spore production process. It is hard to tell whether an Amanita is old enough to drop spores until you get some experience. One trick is to cut a slot the width of the stem half way across an index card and hang the contraption across the open top of a narrow cup or glass. Covering with waxed paper blocks drafts. Give it an hour or so and see if any spores have dropped onto the card. If spores have dropped, the specimen is mature or approaching maturity. Nothing on the card means keep the contraption in place for another hour or so. the contraption can be set up to operate over night. You get both a spore print and a mature specimen for your troubles.

It is good to put a moist paper towel (not wringing wet) in the bottom of the cup or glass (even loosely wrapped around the mushroom’s stem base) in order to keep the moisture level up and encourage “normal” spore inflation.

If mold starts to form on the mushroom’s stem, give up immediately and thoroughly dry the specimen. This will save as much as possible before you lose the whole thing to decay. Usually, mold doesn’t form unless you’ve started with a specimen that is too young to get through its interrupted development before mold sets in.

Very best,


Hi Rod and Debbie
By: Lucy (lucya)
2015-05-05 20:47:31 AST (-0400)

This one was among my very first amanita collections. At this time I was in the bad habit of leaving the ones that didn’t fit in the dehydrator in the fridge overnight and drying them the next day once a space had opened up in the dehydrator. This could have caused weird measurements for a proportion of my specimens (from 2011 and 2012). Luckily my dehaydrator is huge so this only occurred rarely.

There are some general observations.
By: R. E. Tulloss (ret)
2015-05-05 17:21:03 AST (-0400)

Because I am again without a functional computer, I’m going to refer you to the teaching item on all WAO website technical tabs concern writing a “range” of any set of numbers. Ranges and averages and the ranges of averages tell a lot about variation.

Regarding drying. There is uncontrolled drying (a mushroom in a market for example) and controlled drying for scientific purposes in a dryer.

Uncontrolled drying results in spores being made with less and less water available to the process the spores get smaller. Often length will be reduced disproportionately (faster) than width in spores being produced under uncontrolled drying conditions. Controlled dryng should happern rapidly so that few spores are produced before spore production terminates completely. The spores on the gills of a mushroom dried for research purposes will have a side more dependent on the age and condition of the mushroom when dried. Since spore prints are rarely found in herbarium collections, one is forced to rely upon dried specimens for a large amount of information about spores. As long as the specimen seems to have dried well (without strong discoloring from heat or gelatinization (cooking) or burning, the spore data from a dozen or more specimens, will usually give a fairly good idea of the range of spores size and shape based on spore prints or fresh material. The lower end of the range of length, width, and Q may be lower from a mix of dried material than they would be from spore prints alone. The thing most likely to disturb the upper ends of ranges are measuremets take from immature material that had basidia sometimes with less than 4 sterigmata. Not all species do this when the basidiome is immature, but many do. For these reasons I prefer to measure hundreds of spores per species. Ranges and over all averages tend to stabilize when the number of spores measured are in the high 400s approach 500. Statisticians among us will be able to confirm that this is a statistical phenomenon.

What can go wrong? The biggest divergences from expected data can be attributed measuring spores in other than lateral view or measuring spores from material damaged by mold in the herbarium (spores are preferentially eaten by many molds) or measuring spores from badly dried specimens (dried too hot or dried to slowly or “air dried” or "sun dried?).

I hope this response is helpful.

Very best,


question for Rod …
By: Debbie Viess (amanitarita)
2015-05-05 15:36:13 AST (-0400)

how do spore sizes and shapes change with dehydration and then rehydration? what do you use to rehydrate tissues? what do you avoid? how much micro variance is seen within a species?

still trying to make sense of that tiny world …

Spore measurements from this collection added to the WAO website.
By: R. E. Tulloss (ret)
2015-05-05 14:06:47 AST (-0400)

Slight change in ranges and averages on this page:


Very best,


I’m not sure if “albino” is the right word or not. Just my ignorance.
By: R. E. Tulloss (ret)
2015-02-11 01:27:02 AST (-0400)

It seems that a number of different amanitas (with a variety of cap colors) will sometimes produce a white or weakly pigmented fruiting body. Amanita phalloides, A. muscaria, A. velosa, A. roseolamellata, A. brunnescens, A. spreta, and others. Apparently, some trigger for pigment production sometimes fails to “fire.”

Very best,


How interesting!
By: Lucy (lucya)
2015-02-10 19:41:25 AST (-0400)

Are they like little albino roseolamellatas?! Is the second one 65018? I guess this means that the recent one I found (197006) will also turn out to be a white roseolamellata.

This is one of two white-capped collections that have both proven to have…
By: R. E. Tulloss (ret)
2015-02-10 19:30:43 AST (-0400)

the “proposed fungal barcode” sequence identical to that of a more typical (brown or brownish-capped) __roseolamellata.

This might raise a question about the original material of egregia sensu A. E. Wood; and I hope someone will have a chance to sequence Wood’s material of hia “egregia.”

Very best,


The proposal of a name “sensu Wood”
By: R. E. Tulloss (ret)
2011-04-12 23:01:46 AST (-0400)

Lucy was kind enough to send the dried specimen from this observation to me.

While its lamellae are largely immature, the inner quarter or so of each gill was beginning to make spores when the mushroom was dried.

Based on an initial review of the spores and the macroscopic data visible in these photographs, it seems plausible that one of the two specimens that Wood treated as A. egregia was this, possibly undescribed, species.

Lucy and I are hoping to pursue this question further.


Created: 2011-03-26 04:36:23 AST (-0400)
Last modified: 2015-02-10 19:27:55 AST (-0400)
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