Hi Zotto.
I don't have these documents, but I think that Berthet, in his thesis (see extracted pages in the joined PDF) uses the terme acrorhynque.
Best regards.

Hi Nicolas

yes, this is exactly the definition of Chadefaud which Berthet 1964 took up. I have a copy of Berthet but I see that your pdf is able to search for words. Do you have the complete article as pdf? If so I would be happy to have it.
thanks
Zotto

Bien Cher Collègue,

En fait il y a trois définitions de la base des asques, selon Chadefaud 1943, Revue scientifique 81, 77-80, vois aussi BERTHET 1964 Essai Biotaxinimique sur les Discomycètes (thèse Uni de Lyon)

1) le type pleurorhynque, caractérisé par la flexion à 180° de l'article subterminal de hyphe ascogène (crochet dangeardien) soit avec deux septa et deux noyaux

2) le type aporhynque, dont l'article terminal est binucléé, avec un septum

3) le type acrorhynque, dont l'article terminal est uninucléé et le subterminal binucléé, avec un septum

Les deux derniers types, avec un septum étant morphologiquement identiques, hormis le nombre de noyau.

Berthet (o.c.) indique pour (Pustularia insignis) = Hypotarzetta insignis (Berthet & Riousset) Donadini : " .. avoir pu, dans certains cas, mettre en évidence d'une manière extrêmement nette le processus dangeardien du type acrorhynque tel que la décrit Chadefaud 1943 - 1944 et vérifier que l'article terminal est bien uninucléé. Mais ceci ne semble pas général, et nous avons observé d'autres dispositions nucléaires difficiles à interpréter. L'étude de la base des asques sans coloration des noyaux nous a permis de voir, à côté de processus acrorhynque typiques (P. insignis), des processus probablement aporhynques (P. cupularis; P. insignis. Le Type acrorhynque, bien que fréqumment réalisé chez les Pustularia "= Tarzetta", semble donc ne pas être de manière constante ".

Il ressort de ce commentaire, à moins que d'autres études prouvent le contraire, qu'il convient d'être prudent dans l'interprétation ou la désignation des types d'asques ne possédant qu'un simple septum. Compte tenu de ce qui précède est des difficultés de contrôler ce caractère (nombre de noyaux), la prudence conduirait à désigner de manière plus simple les asques, soit possédant un simple septum ou possédant un crochet !

Cordialement et bonne année 2010, à toi et aux tiens.

René

Dear René

many thanks that you went so deep into the matter. I have a similar conclusion, that it is better to avoid the terms with -rhynqe as long as no nuclear observations were made. Since a longer time I think that it is not very useful to apply different terms for the same thing, e.g. concerning croziers and pleurorhynque, but now there is even more reason to avoid the French terms in normal taxonomic work. On the other hand, Chadefaud's interpretation of earlier observations on nuclei in ascogenous hyphae is very intersting and throws some light on the basal protuberances we sometimes see in simple-septate asci, and which might partly belong to the acrorhynque type. In Orbilia there are frequently such outgrowths which do not develop into further asci.

We have also Evi's result when she measured nuclear contents by fluorescence. She found that in the Helotiales simple-septate ascogenous hyphae may be partly monokaryotic and partly dikaryotic, depending on the species (Weber 1992: 68). In the case where each cell contains a single nucleus, this had always the double DNA content, while in a major part of the species investigated a mixture of diplontic monokaryons and haplontic dikaryons occurred.

The case of monokaryotic ascogenous hyphae was unknown to Chadefaud, obviously. So this case would even need a fourth term different from the three introduced by Chadefaud!

I also investigated the question whether clamps and croziers mean the same thing (homology). From cell wall morphology this is undoubtedly so. The dolipore is an ultrastructural difference, but anyhow ascos and basidios could have a common ancestor which already had croziers or clamps (some Ustilaginomycetes have actually no dolipori). The only problem is that Taphrinomycotina (with Neolecta) and Saccharomycotina do not have true croziers (reports of croziers in Endomyces refer to gametangiogamy, in my opinion, see also Gäumann). So either both these groups lost croziers, or croziers developed for the first time in Hyalorbilia and related orbilaceous genera.

Because of the rather basal situation of Orbiliaceae within the ascos, this question caught my interest, but many of the concerned items remain speculative so far.

Zotto

Hi Zotto,

I send you the two papers
Best, Guy

The argument is really interesting, I realize that until now the term aporhynque was most utilized, also when the appropriate one was acrorhynque.
But judging by the drawings by Berthet (as joined by Nicolas), it should be possible to recognize morphologically an aporhynque from an acrorhynque ascus. The aporhynque ascus should be the last element of the hypha, contrarly to the acrorhynque ascus, that arise from the subterminal one. But wat happens to the terminal uninucleate "cell"? Simply remains there, at the base of the ascus? Can it continue growth? I don't think it can returns to be ascogenous because it's uninucleate...

Can you send me the same documents, Guy? Thank you!

Mario

Zotto
I send you the complete Berthet's thesis.
François

Hi Mario

yes, this is the question. I also understand that the uninucleate terminal cell of acrorhynque hyphae does not grow. But when you wish to find out whether ascogenous hyphae are acro- or aporhynque, you will perhaps be unable to decide whether or not the terminal cell grows out to form an ascus. Only when you see that it is binucleate you can be sure it will grow out.

Zotto

Do you think that in the same apothecium should be verified both cases?

I actually do not know how often these two terms, acro- and aporhynque, have ever been applied to fungi. Theoretically it should be possible that a dikaryotic hypha at its end suddenly changes to acrorhynque, but I do not know if such happens. In any case, aporhynque hyphae can become as long as they want, while acrorhynque is a very limited case in which a single dikaryotic cell divides to form two uninucleate and one dikaryotic cell from which a single ascus emerges.

What I once saw (in Proliferodiscus poulveraceus) is that in a single apothecium a mixture of simple-septate hyphae and croziers occurred, and I think I saw even "pseudoclamps" (crozier-like protuberances which do not fuse). I read in papers on basidios that such pseudoclamps have to do with mutations in certain genes, so we should also consider in our fungi that mutations may cause such variation in croziers.

Similar variation is not rare in Lachnellula and other related genera.

Zotto

I read sometimes "aporhynque", that is a diagnostic character in Helvella section Leucomelaenae and for Helvella corium. Donadini also used apo- and pleurorhynque for asci of Peziza. I remember one single usage of the term "acrorhynque", i.e. in the protologue of Helvella dovrensis by Trond Schumacher.
I see every time (not abundants, but presents) some "pseudoclamps", or however protuberances in the asci near the base, in a small alpine form related to Helvella corium (not in the typical H. corium). Sometimes it has puzzled me but at the end I understand these asci was not pleurorhynques (I was persuaded they were aporhinque, but from today I'm not sure anymore...).
I join a small image of this feature ;)