Observation 156371: Roseodiscus rhodoleucus (Fr.) Baral
When: 2004-05-29

Notes: Identified by H.O. Baral as Roseodiscus rhodoleucus (Fr.) Baral [2015-10-08] fide Comments below
Original Herbarium Label: Stamnaria persoonii (Moug.) Fuckel
Growing on dead stems of Equisetum sp.
Roseodiscus equisetinus vel rhodoleucus by Erwin Gruber (HippoMyka) 2015-10-08
Erwin Gruber wrote : “Had a further look on the drawing of spores with dimensions, according to my remebering, these should fit to Roseodiscus rhodoleucus, do appear to be too large for R. equisetinus.” Also 2015-10-08

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Anwers to your comment plus question
By: Erwin Gruber (HippoMyka)
2015-10-10 03:37:38 CDT (-0400)

You are welcome, Oluna and Adolf!

Having written an unpublished master thesis about genus Stamnaria some time ago, i got to know it the best.
You may find some uploads by searches: stamnariophilus + flickr, erwin_pteridophilos + inaturalist, but there are no pics of S. persoonii, didn’t look for it last years, sorry!
To Eq. arvense “var. boreale”, i rather would not accept this “variety”, however fungi specialized on horsetails are not likely to care about casual or regional variations.
I am pretty sure that true Stamnaria persoonii may be found in BC in late spring, better early summer at dead sprouts of Equisetum fluviatile, growing in dense colonies at lakeshores.
The fungus might as well occur at dead E. arvense at suitable sites, yet seems to be rare at this host.
Apart of that there is another specialzed fungus Stamnaria “mougeotii ined!” at E. arvense, obviously much more frequent than S. persoonii in Europe.
You might have chances to find asexual stages of both specialized fungi on dead or dying back E. arvense and fluviatile in autumn, these will turn into ascocarps the following year.
I will tell you when having made photos of.

Kind regards

Thanks for all the help we are getting
By: Oluna & Adolf Ceska (aceska@telus.net)
2015-10-09 11:04:56 CDT (-0400)

Many thanks for all your and Zotto’s help. This fungus was growing on Equisetum arvense var. boreale (Bong.) Rupr., that differs from the E. arvense s. str. by having triangular (not quadrangular) branches.This variety occurs in North America and in northern Europe.
If you would not mind, browse in our Ascomycota MO postings that I collected into this MO list:
Mushroom Observer is a great system for storing and displaying all the graphics that go with the supporting herbarium specimens. Its flowed “naming policy” degrades this great system into a blog run by citizen scientists. Oluna and I greatly appreciate your help as well as the help from other professional (or advanced) mycologists, who are looking at our MO observations.
P.S. What are the “right places and time” to look for Stamnaria persoonii?

Thanks for ID to Zotto
By: Erwin Gruber (HippoMyka)
2015-10-09 07:40:07 CDT (-0400)

Thanks for your kind IDing this ascomycete!
I was not fully certain at first glance, than remembered that R. equisetinus got clearly smaller spores, partially septate ones.
So far i’ve seen the horsetail is E. arvense.
I would rather be wondered if true Stamnaria persoonii was absent from British Columbia, guess one needed just to look for at right places and time.


clearly Roseodiscus rhodoleucus
By: h.baral
2015-10-08 15:21:47 CDT (-0400)

Yes of course, R. rhodoleucus. Spore size perfectly fits my drawing Roseodiscus rhodoleucus, HB 2899.jpg. Would be good to check the iodine reaction of the ascus apex because there exists an undescribed species with inamyloid asci.


Addition to previous ID and comment
By: Erwin Gruber (HippoMyka)
2015-10-08 12:30:20 CDT (-0400)

Had a further look on the drawing of spores with dimensions, according to my remebering, these should fit to Roseodiscus rhodoleucus, do appear to be too large for R. equisetinus.

Disagreement to ID as Stamnaria persoonii, new ID as Roseodiscus sp.
By: Erwin Gruber (HippoMyka)
2015-10-08 12:20:35 CDT (-0400)

These fruitbodies are certainly no Stamnaria sp., but either Roseodiscus equisetinus or R. rhodoleucus.
Spore dimensions and shape should enable to decide between both spp., R. rhodoleucus got larger spores but i am not certain now to which species the drawn spores will fit better.
Please ask H.O. Baral, Zotto, who renamed both fungi.
Maybe i will find the right literature to ID the species.

Created: 2013-12-27 06:13:50 CST (-0500)
Last modified: 2015-10-09 00:41:51 CDT (-0400)
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