Hi Dave,

L. occidentalis should have a hemiamyloid iodine-reaction (red in Lugol's and blue in KOH+Lugols). Attached some asci in Lugol's. Maybe you try again and observe them under immersion.

Regards,

Martin

I must correct that L. occidentalis varies in the iodine reaction. Sometimes one has even both types of asci within the same hymenium (no parasite!). Yours, David, look inamyloid as the apices are hemispherical and very thin-walled above.

L. willkommii is apparently always inamyloid and more parasitic, but I never understood whether it is really different from occidentalis. L. hahniana is said to be a synonym of occidentalis.

In Genbank there is only one sequence of willkommii though it is said to be harmful to Larix.

Here you can download my Lachnellula-key

Zotto

Thank you both Martin and Zotto for your comments about my recent Lachellula collection.

Martin, I appreciate your suggestion that I reexamine more asci in Lugol's.  I have already looked at asci from three apothecia with the 100X oil objective with no sign of iodine reactions.  The material is still fresh and living so I will examine some more asci, perhaps this time with KOH pretreatment.

Zotto, thank you for your comments and for the monograph of Lachnellula, which I didn't have.  It is a great help and based on it I believe my material best fits L. occidentalis, although the iodine reaction remains problemmatic.  I was particularly interested in the section discussing Lachnellula species in xeric habitats.  I live in an area that has been described as a "boreal rainforest", where strongly desiccated branches and twigs are periodically exposed to fog and rain, even occasionally in mid-winter.  This collection of L. occidentalis was on very small twigs (2-4 mm) that had blown down from high up on a large tree.  The previous week they must have been frozen and totally dry.

Dave

yes, most of the species of Lachnellula grow on attached twigs and branches, or on trunks (e.g., L. resinicola). Such a habitat is typical of inamyloid asci, but exceptions prove the rule.

Inamyloidity in occidentalis is not a problem, as I remember. All occurs in that species.

With the three available LSU-sequences of occidentalis/willkommii in GenBank I made an analysis, in conclusion I feel the three all belong to a single species.

Zotto

Hi Dave and Zotto,

some workers claim that L. w. appears only in connection with symptomes of Larix-cancer. Such an example is presented here by Enrique:
http://www.asturnatura.com/fotografia/setas-hongos/lachnellula-willkommii-hartig-dennis-2/3075.html?
He obviously observed a positive iodine reaction in the wall of the ascus-tip only, but not in the apical ring (to make things even more complicated).
Did you see any signs of cancer-growth at your twigs, Dave?

Regards

Martin

Martin, I do not see a positive reaction on Enrique's nice pics. Rather this is the same situation as with David's record. 

Here is my small phylotree.

Zotto

I do see a clear blue reaction of the ascus wall in the upper portion in Enrique's plate (lower left). Maybe Enrique can contribute some additional pictures?

Regards

Martin

Hi Martin & Zotto,

The blue colour in Enrique's picture seems rather diffuse for one of these fungi.  It looks more like something you would see in Peziza.  Perhaps it is an artifact.  Even some of the spores seem a little blue.  I went back to my material and mounted it in Lugol's with KOH pretreatment and still saw no iodine reaction in any ascus.  The base of the asci in my material is similar to Enrique's.  The tree showed no symptoms of disease, other than being thoroughly dead.

Those records of L. occidentalis in GenBank still raise some questions.  The two CBS strains of L. occidentalis and L. willkommii were both from Larix decidua, an exotic species in Massachusetts where they were isolated.  Perhaps they are the same species but with one misidentified.  The other isolate of L. occidentalis in your tree is from Nagano, Japan and perhaps a separate species.  Lachnellula occidentalis is typified by a collection on a native species, Larix occidentalis from British Columbia,Canada.  My collection is on Larix laricina, another native species on the Atlantic coast.  The North Americal collections from native species don't seem to produce galls or other symptoms of disease.  It might be interesting to sequence my material and see where it appears on the tree.  It would also be nice to get some European sequences, particularly of L. willkommii.  I wonder if too Hahn & Ayers cultures are still around.

Dave

Yes, Japan may well have another species. Interesting would be also whether you have in Canada also collections with hemiamyloid (red-reacting) apical rings. These are quite common here in Europe, but inamyloid asci also occur (and mixtures in the same apothecium).

I feel that little molecular work has been done on Lachnellula, which is astonishing, since there are parasites among them.

When I make a BLAST with the willkommii sequence, I get only one occidentalis and two Lachnellula sp., not even unidentified strains referrable to Lachnellula. Likewise with the ITS: only 5 strains of Lachnellula.


Zotto

Dear friends
I don't remember well this collection of L. willkommii. I'm sorry because I have any additional images, but my brief note on this species says: the asci are with croziers, not amyloid, not even hemiamyloid.
The blue shades are artificial. 

Regards
Enrique

Hola Enrique,

thank you for clearing this! I learned now that we have to test this ubiquitous fungus in every Larix stand more often! At least your collection seems to be connected to a cancer growth on the twig.

Regards

Martin

Hi Martin,

Earlier you asked if the trees on my property with Lachnellula had any cankers.  I initially didn't see any, but Saturday I went out to inspect some other trees and found some typical cankers.  Unfortunately the apothecia are immature and I cannot test the asci with Lugol's.  Today I found a site from Prince Edward Island, our neighbouring province, stating that this disease was first seen in New Brunswick in 1980.  Apparently it is a recent arrival.  All this requires further investigation.

Dave

I was looking for further information about this fungus and found this website:

http://www.exoticpests.gc.ca/es-details/disease/1000096?

My home seems to be at the centre of distribution for this exotic species.

Hi Dave,

that makes you the principal source for "further inverstigations"... ;-)
I did search very often for cancer symptoms on twigs of Larix with Lachnellula, but I failed to find some, yet. Next season is close to come...

Are you aware of the thesis of Jean-Yves Blanchette, University of New Brunswick 2001? It is dedicated to the early state of infection, as probably in your case. I will send you a copy, if you don`t have it. Though reproduction of the pictures are lousy...

Regards

Martin

Thanks Martin, that would be very kind.  I don't think we would have that thesis at the New Brunswick Museum where I am based.

As I begin the wake up and become aware the presence of this fungus, I remember last September seeing many small trees of Larix laricina (local people call it "Hackmatack") that had suddenly died.  I should check these for stem cankers.

Dave