Gruppo Micologico G. Bresadola

Amanita submembranacea

A broader view on Amanita

Cornelis Bas

National Herbarium Neederland - P. O. Box 9514 - NL-2300 RA Leiden

Species of Amanita are usually among the first agarics a beginning mycologist learns to recognize. The genus is relatively easy to identify in the field and many of its species too. Therefore one would expect that after about 300 years of mycology in Europe, all of the about 50 species of Amanita in this part of the world are well known. Unfortunately, that is not the case. Particularly in section Vaginatae the situation is far from clear, but also at other places in the genus, e.g. in the A. gemmata-, the A. excelsa- and the A. verna-group considerable problems are still to be solved.

There are several reasons for this unsatisfactory state of affairs. It did take a long time before the classical species were microscopically analysed and from the beginning of this process the lack of type specimens for many of these species turned out to be a severe handicap, leading to differing species concepts. The important discovery that the genus Amanita could be divided into a group of species with amyloid spores and a group of species with non-amyloid spores (subgenera now) was made as late as in 1928 (Gilbert & Kühner). It was not before the sixties that a beginning was made with analysing the so diverse microscopical structures of the volva (= velum universale) in Amanita which clarify the behaviour of the volva in the developing fruit-body and the enormous diversity of volval remnants on mature fruit-bodies.

The storing of (often poorly) dried collections without accompanying good descriptions, particularly without notes on colours (preferably matched with a current colour code) has been another serious handicap, particularly in section Vaginatae. Moreover, especially in the latter section, where accurate description of the shape of the spores is of great importance, progress is hampered by the rather haphazard way in which this shape is still often described; what is subglobose to one author, is ellipsoid to another. In 1969 Bas proposed to standardize these terms in relation to the measured length/breadth of spores. This terms are also applied to the shape of the spores of other agaricoid genera in all 4 volumes of the Flora Agaricina Neerlandica and certainly help mycologists to understand each other better. The genus Amanita is a veritable cosmopolitan one. Species of it have been recorded from all continents, from arctic tundras to tropical rain forests and from lowlands to high mountains. However, in Europe the genus is with about 50 species rather poorly represented. Jenkins (1986) in his book on Amanita in North America enumerates 128 species and mentions that the true number is probably considerably larger. Tulloss & al. (1995) report 58 species for the state of West Virginia alone, of which quite a few are still undescribed. Recently Wood (1998) describes 67 species of Amanita from in and around New South Wales (Australia) of which 34 as new. The number of species recorded from South America, a continent long thought to be unfavoured by the genus Amanita, is slowly but constantly growing and is close to passing 50. In addition the number of species known from the palaeotropics is already rather high and will probably still grow considerably.

The knowledge that Amanita is so very rich in species elsewhere in the world should warn mycologists to be very careful with proposing changes in its infrageneric classification based only on locally known taxa.

It is interesting to see that the infrageneric division of Amanita, in great lines developed by Gilbert (1940) and more precisely defined by Corner & Bas (1962) and Bas (1969), viz. into a subgenus Amanita (with non-amyloid spores) with sections Vaginatae and Amanita and a subgenus Lepidella (with amyloid spores) with sections Phalloideae, Validae, Amidella and Lepidella, can still reasonably well accommodate the many new species being described.

Nowadays, a flood of molecular-phylogenetic studies is being poured out over mycological taxonomists and the genus Amanita does not remain untouched. The result of three of such studies on Amanita, viz. Weiss & al. (1998), Drehmel & al. (1999) and Oda & al. (1999) differ in quite a few details but do not completely turn its internal classification upside down. In all three, however, the annulate species of section Vaginatae sensu Corner & Bas are well separated from the exannulate species. So it seems that a third section, sect. Caesareae Sing. will have to be accepted. Moreover, in all three studies the Amanita citrina group is shown to be closer related to section Validae than to section Phalloideae; a somewhat unexpected but not disagreeable outcome.

Another interesting result is that A. ceciliae (Berk. & Broome) Bas (= 'A . inaurata Secr.') in all three of these publications finds its place in the middle of the exannulate species of the Vaginatae. It certainly should not be placed in a separate section as proposed by Bon (1995; Amanitopsis sect. Inauratae Bon).

It is to be hoped that more of such molecular-phylogenetic studies, preferably including more species, will follow and that molecular analyses of a number of species complexes will help us to understand true relationships better. But it is very improbably that painstaking morphological studies will be no longer necessary. We certainly shall have to continue to find out which morphologically defined species and infraspecific taxa can be distinguished, before we hand them over to molecular mycologists to test them. Sometimes there will be agreement, sometimes it will be shown that morphological taxa have to be merged or split up. But I shall not be astonished when it turns out that morphological taxonomy did not do such a bad job.

References

Bas, C. (1969) - Morphology and subdivision of Amanita and a monograph of its section Lepidella. Persoonia 5: 285-597.

Bon, M. (1975) - Agaricales rares ou nouvelles pour la region du Velay et ses environs. Bull. mens. Soc. linn. Lyon 44: 165-181.

Corner, E.J.H. & Bas, C. (1962) - The genus Amanita in Singapore and Malaya. Persoonia 2: 241-306.

Drehmel, D., Moncalvo, J.-M. & Vilgalys, R. (1999) - Molecular phylogeny of Amanita. Mycologia 91: 610-618.

Gilbert, E.J. (1940) - Amanitaceae 1. In Bresadola, Iconographia mycologica 27(1): 1-200.

Gilbert, E.J. & Kühner, R. (1928) - Recherches sur les spores des Amanites. Bull. Soc. mycol. Fr. 44: 149-154.

Jenkins, D.T. (1986) - Amanita of North America. Eureka, California. Oda, T., Tanaka, Ch. & Tsuda, M. (1999) - Molecular phylogeny of Japanese Amanita species. Mycoscience 40: 57-64.

Singer, R. (1943) - Das System der Agaricales III. Ann. mycol. 41: 1-189. Tulloss, R.E., Stephenson, S.L., Bhatt, R.P. & Kumar, A. (1995) - Studies in Amanita (Amanitaceae) in West Virginia and adjacent areas. Mycotaxon 56: 243-293.

Weiss, M., Yang, Z-L. & Oberwinkler, F. (1998) - Molecular phylogenetic studies in the genus Amanita. Can. J. Bot. 76: 1170-1179.